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The purpose of the current study was to explore the immunomodulatory effects of different adjuvants combined with inactivated vaccines under Aeromonas veronii TH0426 infection in crucian carp. This study explored the best conditions for A. veronii as an inactivated vaccine, and included an animal safety test. Furthermore, we expressed the flagellin FlaA of the A. veronii TH0426 strain for use as an adjuvant supplemented in the diet. Crucian carp were fed 12 different experimental diets for 35 days, including the administration of 10 different adjuvants and inactivated vaccine combinations (50% aluminum hydroxide gel and inactivated vaccine combination, and inactivated vaccine with 20%, 30%, or 50% glucan, astragalus polysaccharide or flagellin), inactivated vaccine alone, and PBS control without adjuvant and inactivated vaccine. After the 42 day feeding trials, the fish were challenged with A. veronii TH0426, and the survival rate over 14 days was recorded. In addition, flagellin FlaA can be expressed normally in large amounts. All experimental groups produced higher levels of IgM serum titres than the control group in the different feeding cycles. Moreover, the activity of serum ACP, AKP, SOD, and LZM, and the expression of inflammatory factors were significantly increased in the experimental groups compared with the control group. The results of qRT-PCR analysis showed that the transcription levels of the IL-10, IL-1β, IFN-γ and TNF-α genes in heart, liver, spleen and kidney tissues were significantly enhanced by adjuvant treatment, indicating that the addition of adjuvants can significantly promote the body's inflammatory response. In addition, the phagocytic activity of leukocytes in each adjuvant treated group was significantly enhanced compared to that in the groups without adjuvant. After the A. veronii challenge, the survival rate of all adjuvant-treated groups was significantly higher than that of the control group, and the 50% flagellin adjuvant group had the highest rate of 78.37%. Overall, our findings strongly indicate that adjuvants not only significantly improve the body's immunity, but also exhibit a strong anti-infection ability. Importantly, this work provides a new perspective for the prevention and control of aquaculture diseases.

Severe acute respiratory syndrome coronavirus 2 variants have continued to emerge in diverse geographic locations with a temporal distribution. The Lambda variant containing multiple mutations in the spike protein, has thus far appeared mainly in South America. The variant harbours two mutations in the receptor binding domain, L452Q and F490S, which may change its infectivity and antigenicity to neutralizing antibodies. In this study, we constructed 10 pseudoviruses to study the Lambda variant and each individual amino acid mutation's effect on viral function, and used eight cell lines to study variant infectivity. In total, 12 monoclonal antibodies, 14 convalescent sera, and 23 immunized sera induced by mRNA vaccines, inactivated vaccine, and adenovirus type 5 vector vaccine were used to study the antigenicity of the Lambda variant. We found that compared with the D614G reference strain, Lambda demonstrated enhanced infectivity of Calu-3 and LLC-MK2 cells by 3.3-fold and 1.6-fold, respectively. Notably, the sensitivity of the Lambda variant to 5 of 12 neutralizing monoclonal antibodies, 9G11, AM180, R126, X593, and AbG3, was substantially diminished. Furthermore, convalescent- and vaccine-immunized sera showed on average 1.3–2.5-fold lower neutralizing titres against the Lambda variant. Single mutation analysis revealed that this reduction in neutralization was caused by L452Q and F490S mutations. Collectively, the reduced neutralization ability of the Lambda variant suggests that the efficacy of monoclonal antibodies and vaccines may be compromised during the current pandemic.

Effective vaccines are essential for controlling the coronavirus disease 2019 (COVID‐19) pandemic. CoronaVac, which is an inactivated virus vaccine, was the first imported COVID‐19 vaccine in Thailand. To investigate the safety and immunogenicity of CoronaVac within the Thai population, we conducted a prospective cohort study among health care workers aged 18–59 years, who received a 2‐dose regimen of CoronaVac 21 days apart between March and April 2021 at the hospital in Samut Sakhon, Thailand. We recruited 185 participants with a mean age of 32 years. Total antibodies against receptor‐binding domain (RBD) and immunoglobulin G (IgG) against nucleocapsid (N) protein of SARS‐CoV‐2 were tested. Total antibodies against RBD were negative before immunization. One volunteer was positive for N, although negative for the RBD antibodies. The seroconversion rate of total antibodies against RBD after the first CoronaVac dose was 67% with a Geometric mean concentration (GMC) of 1.98 U/ml. Following CoronaVac dose 2, the seroconversion rate increased to 100% with a GMC of 92.9 U/ml. The seroconversion rates of IgG against N protein were 1% after dose 1 and 62.8% after dose 2. The overall incidence of adverse reactions was 59.5%. Injection‐site pain was the most common local adverse event (52.4%), while myalgia was the most common systemic adverse event (31.9%). No serious adverse events were observed. A 0–21 days, 2‐dose CoronaVac regimen appears safe, inducing a satisfactory response compared with convalescent serum obtained 4–6 weeks postnatural infection. Antibody responses after 2‐dose CoronaVac were comparable to the convalescent plasma but waned rapidly after 3 months. Therefore, we recommend 2‐dose CoronaVac administration with possible booster doses.

Introduction Vaccines generally have reduced effectiveness in hemodialysis patients and a similar condition may also apply for the SARS-CoV-2 vaccines. The aim of this study was to analyze humoral responses of hemodialysis patients to SARS-CoV-2 vaccines. Methods Eighty-five maintenance hemodialysis patients who received either inactivated or mRNA SARS-CoV-2 vaccines were investigated. Antibody levels were measured by a commercial antibody kit, which detected antibodies towards receptor binding domain of the SARS-CoV-2 spike protein. Comparative analyzes were carried between vaccine groups and with a control group of 103 healthy volunteers. Results Seropositivity rate and antibody levels were significantly lower in hemodialysis patients who received inactivated vaccine (p=0,000). While mRNA vaccine had better immunogenicity, both vaccines protected from symptomatic infection when seropositivity was achieved. Discussion/conclusions When used in the same dose with the general population, inactivated SARS-CoV-2 vaccines generate reduced humoral response in hemodialysis patients. mRNA vaccines have better immunogenicity in this group. This article is protected by copyright. All rights reserved.

The common goal of all vaccines developed against COVID‐19, although they have been designed with different methods, is to develop an effective immunity and antibody response against SARS‐CoV‐2. However, the postvaccination immune response and antibody levels differ between individuals. This study examined the relationship between postvaccine seropositivity rates, age, gender, smoking, and body mass index (BMI), and antibody titers. A total of 314 healthcare workers (HCW) who were not previously infected with COVID‐19 and who had received two doses of CoronaVac inactivated vaccine participated in the study. Seropositivity against the receptor‐binding domain (RBD) of the SARS‐CoV‐2 spike protein was measured from the participants 4 weeks after the second dose of vaccine using the electrochemiluminescence (ECLIA) method. In addition, the antibody developed against the nucleocapsid protein (NCP) was evaluated and compared using Elecsys Anti‐SARS‐CoV‐2 kit. One hundred and eighty‐one of the participants were female (57.6%) with a median age of 39 (interquartile range [IQR], 10) and 133 (42.4%) were male with a median age of 41 (IQR, 11). 99.6% of the volunteers developed seropositivity 4 weeks after the second dose of vaccine. It was also observed that the rate of RBD protein antibody titer was >250 U/ml in smokers, which is quite low compared to nonsmokers (p = 0.032), and that high RBD antibody titers were proportionally lower in obese participants, according to BMI values, compared to those with normal BMI (49.5% and 9.9%). It was observed that seropositivity developed in almost all participants after the CoronaVac vaccine. However, it was determined that the antibody titer measured varied depending on factors such as smoking, BMI, and duration.

ObjectivePatients with malignancy suffer from a compromised immune system due to either the effects of malignancies or treatments. Cancer patients are at higher risk of different infections particularly SARS-CoV2 and usually produce weaker response to vaccines. The aim of this study was to evaluate the safety and immunogenicity of the inactivated SARS-CoV-2 vaccine (Sinopharm, BBIBP-CorV) in patients with malignancy.Material and MethodIn total 364 patients with cancer (median age: 54 years old, F/M ratio: 217/147) who received two doses of Sinopharm vaccine were enrolled in this study. Vaccine related side effects was assessed by a questionnaire and the presence of SARS-CoV-2 anti-Spike protein (S) IgG and neutralizing antibody two months following vaccination were measured by immunological methods.ResultsInjection site pain and fever were the most common local and systemic side effects in vaccine receivers. Two months after the first dose, anti-S IgG and neutralizing antibody were detectable in 77.1% and 80.7% of all participants, respectively with an overall response to either or both measured in 86.9% of patients The rate of seroconversion was lower in older age, those with hematological malignancies and chemotherapy receivers.ConclusionThe result of study confirmed the safety and short-term efficacy of Sinopharm inactivated vaccine (BBIBP-CorV) in patients with different type of malignancies.

Vaccination is one of the most effective and versatile ways to prevent infectious diseases. The development of modern technologies makes it possible to obtain vaccines with desired properties. The review presents data on different types of vaccines used for the prevention of infectious diseases of birds. The advantages and disadvantages of traditional attenuated and inactivated vaccines, as well as recombinant vaccines vector, subunit, based on virus-like particles and DNA vaccines are considered. Possibilities of bacterial, yeast, baculovirus and plant systems for the expression of heterologous genes for the production of recombinant vaccines are discussed.

Rapid development of COVID-19 vaccines has helped mitigating SARS-CoV-2 spread, but more equitable allocation of vaccines is necessary to limit the global impact of the COVID-19 pandemic and the emergence of additional variants of concern. We have developed a COVID-19 vaccine candidate based on Newcastle disease virus (NDV) that can be manufactured at high yields in embryonated eggs. Here, we show that the NDV vector expressing an optimized spike antigen (NDV-HXP-S) is a versatile vaccine inducing protective antibody responses. NDV-HXP-S can be administered intramuscularly as inactivated vaccine or intranasally as live vaccine. We show that NDV-HXP-S GMP-produced in Vietnam, Thailand and Brazil is effective in the hamster model. Furthermore, we show that intramuscular vaccination with NDV-HXP-S reduces replication of tested variants of concerns in mice. The immunity conferred by NDV-HXP-S effectively counteracts SARS-CoV-2 infection in mice and hamsters., Here the authors show that a Newcastle disease virus based COVID-19 vaccine expressing a stabilized spike protein induces protective immunity in small animal models and reduces replication of variants of concerns. This vaccine candidate can be produced by influenza virus vaccine manufactures around the world.

Neutralizing antibodies in volunteers who received two doses of an inactivated SARS-CoV-2 vaccine deceased over several months. A three-dose procedure study suggested that the boost conferred by a third dose rescued the waning of neutralizing antibodies after the two doses of the inactivated vaccine. Importantly, a booster dose can also elicit a more robust neutralizing antibody response than the two-dose procedure. This article is protected by copyright. All rights reserved.

Avian influenza (AI) is a respiratory disease complex syndrome recently recorded in vaccinated flocks causing high economic losses. This study aimed to prepare inactivated vaccine from recently isolated field strains [highly pathogenic avian influenza (HPAI) (H5N8) and low pathogenic avian influenza (LPAI) (H9N2)] and compare the efficiency of the two experimental avian influenza vaccines and some commercial avian influenza H5 and H9N2 vaccines in laying hens. The obtained results indicated that the identified experimental vaccines (H5N8 and H9N2) were protected the flocks from AI as compared to commercial H5N1, H5N3, and H9N2 vaccines, which showed a protection level of 80, 70, and 90%, respectively, indicating a high efficacy for the developed vaccines. In addition, it significantly improved the virus shedding, especially when used in booster dose. The experimental vaccines were given high antibody titer higher than commercial vaccine which was reached to 9.3 log2, 9.7log2 for experimental H5N8 vaccine which was significantly higher than and groups 3 and 4 especially at 2nd WPV, while at the 3rd WPV, the significant difference was with group 4 only. The HI titer was 9.3 log2 at 2nd WPV for the experimental H9N2 vaccine that was significantly higher than group 9. In conclusion, the booster dose of the experimental vaccines could elicit strong immunity than single-dose and commercial vaccines.

Since the outbreak of COVID-19, a variety of vaccine platforms have been developed. Amongst these, inactivated vaccines have been authorized for emergency use or conditional marketing in many countries. To further enhance the protective immune responses in populations that have completed vaccination regimen, we investigated the immunogenic characteristics of different vaccine platforms and tried homologous or heterologous boost strategy post two doses of inactivated vaccines in a mouse model. Our results showed that the humoral and cellular immune responses induced by different vaccines when administered individually differ significantly. In particular, inactivated vaccines showed relatively lower level of neutralizing antibody and T cell responses, but a higher IgG2a/IgG1 ratio compared with other vaccines. Boosting with either recombinant subunit, adenovirus vectored or mRNA vaccine after two-doses of inactivated vaccine further improved both neutralizing antibody and Spike-specific Th1-type T cell responses compared to boosting with a third dose of inactivated vaccine. Our results provide new ideas for prophylactic inoculation strategy of SARS-CoV-2 vaccines.

Introduction: Klebsiella pneumoniae superbug is emerging as a serious health concern as resistance to last-resort antibiotics spreads. To bypass the therapeutic molecules used today, the development of an immunoprophylactic safe approach is of great clinical relevance. This study was conducted to determine the protective efficacy of antibodies elicited by killed vaccine against multidrug-resistant (MDR) K. pneumoniae. Materials and Methods: In this study, heat-killed MDR K. pneumoniae isolated from different clinical samples were employed for the intradermal immunization of 10 BALB/c mice. Two weeks after the third dose of immunization, the mice were intraperitoneally challenged with live K. pneumoniae and observed for 14 days. Tail blood was collected 7 days after each booster followed by cardiac puncture 14 days postchallenge. Bactericidal activity and antigen-binding capacity of the serum antibody produced by the vaccine were evaluated by serum bactericidal antibody (SBA) assay and ELISA, respectively. Results: In this study, 80% survival rates were observed at 14 days postchallenge among the immunized mice. Regarding SBA assay, 100% bactericidal activity of the immunized mouse sera was observed using 50% guinea pig complement at 1:10 serum dilution after 3 h of incubation, and all the pre- and postchallenge immunized serum immunoglobulin G antibody had significantly higher optical density values comparing the control mice in ELISA. Conclusion: In our study, intradermal immunization with heat-killed MDR K. pneumoniae produced protective antibodies in BALB/c mice. These findings suggest that the use of a first-generation vaccine provides the supply of a larger number of candidate antigens for eliciting required immune response.

Newcastle disease virus (NDV), a major pathogen of poultry worldwide, causes significant economic losses in the poultry industry. To characterize the ability of recently isolated virulent strains of NDV genotypes VI and VII to cause disease in quails, and to evaluate the efficacy of two NDV vaccines against such strains, Japanese quails were experimentally inoculated with either NDV genotype VI (Pigeon F-VI strain) or VII 1.1 (GHB-328 strain) with or without vaccination with inactivated NDV vaccine of genotype II (La Sota strain) or VII (KBNP strain). Mild to severe neurological signs developed in quails inoculated with the Pigeon F-VI strain from 3 to 14 days post infection (PI) and from 4 to 10 days PI in birds infected with the GHB-328 strain. The mortality rates were 46% and 33% for birds inoculated with NDV VI and NDV VII 1.1, respectively. The severity of histopathological changes depended on the viral isolates used. Vaccination with the La Sota or KBNP vaccine strain successfully protected quails against NDV-induced mortality and decreased the severity of clinical signs, pathological changes and cloacal viral shedding. This study showed that these virulent NDV isolates had mild to moderate pathogenicity in quails and that both vaccines protected against challenge with both virus strains. NDV vaccine genotype VII improved the level of protection against challenge with the VII 1.1 genotype compared with the classic vaccine, but failed to protect quails against challenge with the VI genotype.

The present study was conducted to evaluate the immune-stimulating effect of CpG-ODN (Toll-like-receptor-agonist21) on broiler chickens vaccinated against Newcastle disease. The motifs were examined with different vaccination programes using different inoculation routes. 270 (one-day-old) - chicks were divided into 6 groups. Group one as a negative control sham inoculated with PBS; group two was injected intramuscularly with CpG-ODN; group three was vaccinated with live ND vaccine by eye-drop route; group four was vaccinated by eye-drop route and injected with CpG-ODN; group five was vaccinated with Newcastle disease inactivated vaccine and injected intramuscularly with CpG-ODN; group six was vaccinated by eye-drop route with live attenuated vaccine dissolved in CpG-ODN. Antibodies responses were monitored based on hemagglutination inhibition test and ELISA assay for the detection of IgG. The average body weight gain and feed conversion ratio were estimated to evaluate CpG-ODN growth-promoting effect. All vaccinated groups supplied with CpG-ODN recorded higher antibodies titer than the only vaccinated group. Group 4 which vaccinated and inoculated intra-muscularly with CpG-ODN recorded higher antibodies titer than other vaccinated groups. Antibodies titer was similar in group five and six without significant difference and both were lower than group 4. ELISA assay confirmed the significance between the adjuvanted groups at 21 and 35 days old. There were no significant differences (p≥0.05) observed between the vaccinated and adjuvated groups in either average body weight gain or in feed conversion rate. In conclusion, CpG-ODN proved its efficiency as an adjuvant when co-inoculated with Newcastle disease vaccines via different administration routes.

Background and Aim: Equine herpesvirus-1 infection in horses causes a wide range of manifestations affecting the respiratory tract. The virus can cause serious economic losses through sporadic abortion in pregnant mares, perinatal death, respiratory disease in young foals. This study was designed to prepare inactivated equine herpesvirus-1 (EHV-1) vaccine using both 0.005 M binary ethylenimine (BEI) and 0.0006% formaldehyde (FA) to decrease the use of BEI and provide a good immunological response. The efficacy, safety, and duration of immunity of the prepared inactivated EHV-1 vaccine were evaluated. Materials and Methods: The prepared FA/BEI-inactivated EHV-1 vaccine was adjuvanted with Alhydrogel and then evaluated by inoculation into guinea pigs, followed by comparison with the commercial inactivated EHV-1 vaccine. These two vaccines were evaluated by testing the safety and immunogenicity in horses classified into two groups. Group A was vaccinated with two doses of the prepared vaccine at a 4-week interval, while Group B was vaccinated with two doses of the commercial vaccine only. Anti-EHV-1 antibodies were detected in horse serum using enzyme-linked immunosorbent assay (ELISA) and virus neutralizing test (VNT). Results: Regarding the time required to inactivate EHV-1 vaccine, this was decreased using 0.005 M BEI and 0.0006% FA from 24 to 8 h. ELISA in Group A horses demonstrated a significant increase in EHV-1 antibody titer at 2 weeks after the booster dose compared with that for the pre-booster one, from 485 to 855 antibody titer, which then peaked at 1240 in the 3rd month post-vaccination; after that, it began to decline gradually until the 6th month. Meanwhile, in Group B, the ELISA reading increased from 420 to 790 and then peaked at 1215. The VNT mean in Group A increased from 1.1 to 2.5 within 2 weeks after administration of the booster dose, while in Group B it increased from 0.8 to 2.1. Moreover, ELISA in Group A pigs indicated mean antibody titers at the 3rd week post-inoculation of 576 for Group A and 554 for Group B. Conclusion: The inactivated EHV-1 vaccine, with fewer chemicals, was prepared in a shorter time. It is safe and also more potent to protect horses for up to 6 months against EHV-1 infection than the commercially produced vaccine.

Equine influenza virus (EIV), is of the important commen and important respiratory infectious diseases of horses. Vaccination can reduce the the prevalence and severity of disease. In the current study, a trial to improve the strength and duration of immune response through using of montanide oil ISA 206, saponin and Mycobacterium pheli extract as adjuvants for an egg grown inactivated EIV [A/equine/Alexandria/1/08 (H3N8)]. Safety and potency of the prepared vaccine studied by inoculation into guinea pigs and horses then evaluated using Haemagglutination inhibition (HI) test for humeral immune response. Cellular immune response evaluated in horses inoculated with inactivated EIVvaccine adjuvanted with Mycobacterium pheli extract using lymphocyte blastogenesis. The vaccines were safe for g.pigs and horses which inducing HI antibodies titer that persist for 10 months post-inoculation in vaccinated horses. EI vaccine adjuvanted with montanide oil ISA 206 was more potent than the other vaccines adjuvanted either with saponin or M.pheli extract. EI vaccine adjuvanted with montanide oil ISA 206 also keeps at 4oC for over one year and at room temperature for 6 months without effect on its immunogenic characters.

OBJECTIVES: Dermatophytosis is a group of cutaneous diseases widely distributed in human and animals. It causes serious infection in some human cases and economic losses in farm animals. The primary aim of this study is to conduct an investigation of prophylaxis and a potential therapeutic vaccine against dermatophytosis. MATERIALS AND METHODS: The rabbit was chosen as an animal model of dermatophytosis for a case control study conducted in two parts. Inactivated cells of Trichophyton mentagrophytes were prepared for use as a vaccine. The prophylaxis part included vaccination of rabbits with the prepared vaccine either alone or with Freund’s adjuvant, followed by infection with the same fungus. The second part included treatment of infected rabbits with an inactivated vaccine. RESULTS: The prepared vaccine showed prophylactic ability against infection with T. mentagrophytes for more than 6 months without requiringan adjuvant and also revealed at herapeutic ability in infected animals after a short time (16 days), compared with the control group. CONCLUSION: Inactivated vaccine gives animals durable protection and shortens the treatmenttime for infection with dermatophytosis.

Neutralizing antibodies in the subjects of an inactivated SARS-CoV-2 vaccine clinical trial showed a decreasing trend over months. An investigation studying the third immunization suggested that the waning of neutralizing antibodies in individuals administered two doses of inactivated vaccine does not mean the disappearance of immunity.

Radiation inactivation of enveloped viruses occurs as the result of damages at the molecular level of their genome. The rapidly emerging and ongoing coronavirus disease 2019 (COVID-19) pneumonia pandemic prompted by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now a global health crisis and an economic devastation. The readiness of an active and safe vaccine against the COVID-19 has become a race against time in this unqualified global panic caused by this pandemic. In this review, which we hope will be helpful in the current situation of COVID-19, we analyze the potential use of γ-irradiation to inactivate this virus by damaging at the molecular level its genetic material. This inactivation is a vital step towards the design and development of an urgently needed, effective vaccine against this disease.

SARS-CoV-2 variants could induce immune escape by mutations on the receptor-binding domain (RBD) and N-terminal domain (NTD). Here we report the humoral immune response to circulating SARS-CoV-2 variants, such as 501Y.V2 (B.1.351), of the plasma and neutralizing antibodies (NAbs) elicited by CoronaVac (inactivated vaccine), ZF2001 (RBD-subunit vaccine) and natural infection. Among 86 potent NAbs identified by high-throughput single-cell VDJ sequencing of peripheral blood mononuclear cells from vaccinees and convalescents, near half anti-RBD NAbs showed major neutralization reductions against the K417N/E484K/N501Y mutation combination, with E484K being the dominant cause. VH3-53/VH3-66 recurrent antibodies respond differently to RBD variants, and K417N compromises the majority of neutralizing activity through reduced polar contacts with complementarity determining regions. In contrast, the 242–244 deletion (242–244Δ) would abolish most neutralization activity of anti-NTD NAbs by interrupting the conformation of NTD antigenic supersite, indicating a much less diversity of anti-NTD NAbs than anti-RBD NAbs. Plasma of convalescents and CoronaVac vaccinees displayed comparable neutralization reductions against pseudo- and authentic 501Y.V2 variants, mainly caused by E484K/N501Y and 242–244Δ, with the effects being additive. Importantly, RBD-subunit vaccinees exhibit markedly higher tolerance to 501Y.V2 than convalescents, since the elicited anti-RBD NAbs display a high diversity and are unaffected by NTD mutations. Moreover, an extended gap between the third and second doses of ZF2001 leads to better neutralizing activity and tolerance to 501Y.V2 than the standard three-dose administration. Together, these results suggest that the deployment of RBD-vaccines, through a third-dose boost, may be ideal for combating SARS-CoV-2 variants when necessary, especially for those carrying mutations that disrupt the NTD supersite.

Vaccination with inactivated bacterin is the most popular and practical measure to control enzootic pneumonia. After immunisation with inactivated bacterin, Mycoplasma hyopneumoniae colonised on the respiratory tract and lung stimulates the humoural immune responses and produces IgG and IgA antibodies. ELISA is a widely used serological method to detect M. hyopneumoniae antibodies. However, commercial IgG‐ELISA kit cannot distinguish between inactivated bacterin‐induced hyperimmune sera and convalescent sera stimulated by natural infection. SIgA‐ELISA method needs to collect nasal swabs, but collecting nasal swabs is not easy to operate. Establishment of a discriminative ELISA detecting humoural IgG from convalescent sera but not hyperimmune sera facilitates to evaluate the natural infection of M. hyopneumoniae after inactivated bacterin vaccination. We expressed and purified a recombinant protein named Mhp366‐N which contains an epitope recognised by the convalescent sera but not hyperimmune sera. The developed discriminative IgG‐ELISA could discriminate between inactivated bacterin‐induced hyperimmune sera and convalescent sera and was reproducible, sensitive and specific to M. hyopneumoniae antibody produced by natural infection. Compared to SIgA‐ELISA method, discriminative IgG‐ELISA was more convenient to detect IgG antibody from sera than IgA from nasal swabs, although it has limited sensitivity in the early stages of infection. Additionally, to some extent, it has a potential to avoid the interference of maternally derived IgG antibodies. The established discriminative IgG‐ELISA was efficient to judge the serological IgG antibodies induced from natural infection or inactivated vaccine stimulation and provided a useful method to investigate and evaluate the live organism infection after the application of inactivated bacterin., An indirect IgG‐ELISA was developed to evaluate M. hyopneumoniae infection but not bacterin vaccination. The method was reproducible, sensitivity and specificity. This method was comparable to SIgA‐ELISA but more convenient.

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused more than 96 million infections and over 2 million deaths worldwide so far. However, there is no approved vaccine available for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the disease causative agent. Vaccine is the most effective approach to eradicate a pathogen. The tests of safety and efficacy in animals are pivotal for developing a vaccine and before the vaccine is applied to human populations. Here we evaluated the safety, immunogenicity, and efficacy of an inactivated vaccine based on the whole viral particles in human ACE2 transgenic mouse and in non-human primates. Our data showed that the inactivated vaccine successfully induced SARS-CoV-2-specific neutralizing antibodies in mice and non-human primates, and subsequently provided partial (in low dose) or full (in high dose) protection of challenge in the tested animals. In addition, passive serum transferred from vaccine-immunized mice could also provide full protection from SARS-CoV-2 infection in mice. These results warranted positive outcomes in future clinical trials in humans. Supplementary Information The online version contains supplementary material available at 10.1007/s12250-021-00376-w.

The results of the study on the specific prevention of infectious diseases in horses are presented. Methods have been developed to increase the immunogenicity of environmentally friendly vaccines against strangles, caused by the beta-hemolytic streptococcus – Sreptococcus equi. The work was carried out in laboratory conditions and horse breeding farms of the Republic of Sakha (Yakutia). The toxicity and immunogenicity of the vaccine was determined by conventional methods on young horses. Based on the study of the immunobiological reactivity of young horses, the use of immunomodulators in the development of inactivated vaccine preparations has been substantiated. Vaccines with immunomodulators were tested and registered in accordance with approved research methods for medicinal products for veterinary use. Polyribonate (polyvedrim) and culture liquid (fugate) from the bacterial strain Bacillus subtilis TNP-3 were used in the composition of vaccines as an immunomodulator. To prepare a vaccine against strangles, strains of bacteria Streptococcus equi H-34 and Streptococcus equi "H-5/1" were used, which were deposited in the Russian State Collection of Microorganism Strains of the Russian State Center for Animal Feed and Drug Standardization and Quality. After immunization with inactivated vaccines containing immunomodulators, the effectiveness of vaccines increases by 20% and reaches 90%. Vaccines increase the body's immunobiological reactivity. The most effective were the “Tabyn” vaccine and the vaccine from the Streptococcus equi strain H-5/1 with fugate, the Bacillus subtilis strain TNP-3. The polyribonate vaccine was approved in Russia (2000), the “Tabyn” vaccine is used in Kazakhstan (2018). These vaccine preparations, which ensure high antiepizootic efficacy, are environmentally friendly, since they do not contain toxic substances and antibiotics.

Leptospirosis is a widespread zoonosis in Russia. The human leptospirosis vaccine produced by Rostov Research Institute of Microbiology and Parasitology has been used since 1998 to minimise risks associated with deterioration of epidemiological situation. Lately, there has been an increase in the incidence of leptospirosis caused by Leptospira interrogans serovar Canicola which is not included in the human vaccine. The aim of the study was to analyse biological properties of Leptospira interrogans serovar Canicola strains to substantiate their inclusion into human leptospirosis liquid concentrated inactivated vaccine. Materials and methods: two L. interrogans serovar Canicola strains: Udalov 480 and Sobaka 2000 were used in the study. Virulent properties of the strains were evaluated by infecting Syrian hamsters, the data on specific activity of the experimental vaccine were compared to specific activity of the leptospirosis liquid concentrated inactivated vaccine used for disease prevention. The experimental vaccine was tested for Specific safety and Abnormal toxicity according to FS.3.3.1.0014.15 Leptospirosis liquid concentrated inactivated vaccine. Results: the comparison of Udalov 480 and Sobaka 2000 strains of L. interrogans serovar Canicola revealed higher virulence of Udalov 480. The tests performed for the experimental vaccine batches demonstrated that the inclusion of Udalov 480 strain did not affect the above-mentioned properties of the vaccine. Conclusions: the study demonstrated the possibility of using L. interrogans serovar Canicola strain Udalov 480 as a component of the currently produced vaccine, and confirmed the safety and efficacy of the new vaccine.

In 2019, the situation regarding Newcastle disease in the Russian Federation worsened radically due to the spread of NDV subgenotype VII-L throughout the country from the Primorsky Krai to the Kursk Oblast. As a result, 17 infected settlements with backyard farms where unvaccinated poultry was kept were registered. In this study, immunogenicity of the vaccines produced by the FGBI “ARRIAH”, as well as the effectiveness of various vaccination schedules to prevent genotype VII NDVs, relevant for the Russian Federation, was studied. It is known that the currently circulating ND agent is significantly more virulent compared to the viruses isolated in previous years, and it is able to bypass the immunity provided by live vaccines. Test results demonstrated that the vaccines against genotype VII NDVs produced by the FGBI “ARRIAH” are highly immunogenic, which allows to effectively prevent the disease when using them as part of a standard vaccination schedule. A 2-dose vaccination schedule using live vaccine from the La Sota strain as well as the “complete” vaccination schedule using inactivated vaccines provides immunity in 100% of chicks. The use of live vaccines in a single- and double-dose vaccination schedules prevents mortality and clinical disease in poultry, but does not prevent virus replication, while the addition of an inactivated vaccine to the immunization schedule does prevent the replication of the virulent virus. Thus, the use of domestically produced live and inactivated vaccines, primarily the ones containing the La Sota strain, with the following control of the immunity level and booster vaccination, if required, is the main tool for the disease control.

Enterovirus A71 (EV-A71) inactivated vaccines have been widely inoculated among children in Kunming City after it was approved. However, there was a large-scale outbreak of Enteroviruses (EVs) infection in Kunming, 2018. The epidemiological characteristics of HFMD and EVs were analysed during 2008–2018, which are before and three years after EV-A71 vaccine starting to use. The changes in infection spectrum were also investigated, especially for severe HFMD in 2018. The incidence of EV-A71 decreased dramatically after the EV-A71 vaccine starting use. The proportion of non-CV-A16/EV-A71 EVs positive patients raised to 77.17–85.82%, while, EV-A71 and CV-A16 only accounted for 3.41–7.24% and 6.94–19.42% in 2017 and 2018, respectively. CV-A6 was the most important causative agent in all clinical symptoms (severe HFMD, HFMD, Herpangina and fever), accounting from 42.13% to 62.33%. EV-A71 only account for 0.36–2.05%. In severe HFMD, CV-A6 (62.33%), CV-A10 (11.64%), and CV-A16 (10.96%) were the major causative agent in 2018. EV-A71 inactivated vaccine has a good protective effect against EV-A71 and induced EVs infection spectrum changefully. EV-A71 vaccine has no or insignificant cross-protection effect on CV-A6, CV-A10, and CV-A16. Herein, developing 4-valent combined vaccines is urgently needed.

H9N2 avian influenza viruses (AIV) continue to circulate in vaccinated chicken flocks in China, which prompted us to investigate the differential immune protection factors induced by H9N2 AIV infection and immunization for analyzing the reason of protection deficiency of H9N2 AIV inactivated vaccine. In this study, we firstly explored virus-induced optimal immune responses in chicken after H9N2 AIV infection. And, we found that H9N2 hemagglutination inhibition (HI) antibody level, antiviral interferon-stimulated genes including 2',5'-oligoadenylate synthetase-like and myxovirus resistance 1, CD8+ T cell response in peripheral blood lymphocytes (PBL) accompanied by the cytotoxicity-associated genes, including poly (ADP-ribose) polymerase and IFN-r play important roles in defending against H9N2 infection. Besides, we observed that vaccine immunization triggered the similar H9N2 HI antibody level as viral infection, the increase of CD4+ T cell percentage instead of CD8+ T cell percentage in PBL. Moreover, we further made a comparative analysis of immune-related gene expression profile in PBL and lung after H9N2 AIV infection and immunization, respectively. The results showed that vaccine immunization contributed to the up-regulation of Th2 cytokine. But the deficiency of cytotoxicity-associated genes induced by H9N2 AIV inactivated vaccine may be the potential key reason of protection deficiency. These findings provide evidence and direction for developing effective H9N2 AIV vaccines.

Currently, the widely used vaccine against duck Tembusu virus (DTMUV) disease is inactivated vaccine which, however, facing the limits of large inoculation dose, short immunization period, and incomplete effectiveness. Access to efficient adjuvants aiding for DTMUV inactivated vaccine seems to be of critical importance. Interleukin-2 (IL-2) was reported to induce a persistent expansion of effector T cells and could be a promising molecular adjuvant for many kinds of vaccines. In this study, the efficacy of duck interleukin (dIL)-2 as an adjuvant for a DTMUV inactivated vaccine was evaluated. Fifty-five Pekin ducks were divided into 5 groups and intramuscularly administered with 5 batches of vaccines at 42 D (A: DTUMV + dIL-2; B: 1/2DTUMV + dIL-2; C: DTUMV; D: 1/2DTUMV and E: PBS), respectively, and received the second vaccination 2 wk later. Fifty-six days after immunization, 6 ducks from each group were randomly selected to conduct a challenge protection test. Antibody titers and cytokine responses were detected to assess humoral and cellular immune responses in serum of inoculated ducks by hemagglutination inhibition and ELISA, respectively; virus isolation and RT-PCR method were used in immunity protective test. Our results showed that dIL-2 exerted an enhanced effect on the vaccine while reducing the dose of inoculated antigen highlighting high adjuvanticity of IL-2. The vaccines supplemented with IL-2 induced a higher level of antibodies and higher percentage of inhibition values than inactivated vaccines without IL-2 to a significant extent. The production level of IFN-α, IFN-γ, and IL-6 genes were elevated, enhancing both humoral and cellular responses. Furthermore, it provided higher protection after virus challenge. Therefore, IL-2 can be considered as a potential adjuvant for inactivated vaccine against DTMUV disease.

The ongoing COVID-19 pandemic is causing huge impact on health, life, and global economy, which is characterized by rapid spreading of SARS-CoV-2, high number of confirmed cases and a fatality/case rate worldwide reported by WHO. The most effective intervention measure will be to develop safe and effective vaccines to protect the population from the disease and limit the spread of the virus. An inactivated, whole virus vaccine candidate of SARS-CoV-2 has been developed by Wuhan Institute of Biological Products and Wuhan Institute of Virology. The low toxicity, immunogenicity, and immune persistence were investigated in preclinical studies using seven different species of animals. The results showed that the vaccine candidate was well tolerated and stimulated high levels of specific IgG and neutralizing antibodies. Low or no toxicity in three species of animals was also demonstrated in preclinical study of the vaccine candidate. Biochemical analysis of structural proteins and purity analysis were performed. The inactivated, whole virion vaccine was characterized with safe double-inactivation, no use of DNases and high purity. Dosages, boosting times, adjuvants, and immunization schedules were shown to be important for stimulating a strong humoral immune response in animals tested. Preliminary observation in ongoing phase I and II clinical trials of the vaccine candidate in Wuzhi County, Henan Province, showed that the vaccine is well tolerant. The results were characterized by very low proportion and low degree of side effects, high levels of neutralizing antibodies, and seroconversion. These results consistent with the results obtained from preclinical data on the safety.

BACKGROUND African horse sickness (AHS) is a devastating viral disease of equids that was first recorded in 1327. Currently, prevention and control of the disease are based on attenuated vaccines and midge control. It has been shown that attenuated Orbivirus vaccines are not always safe as they may reverse to virulence. OBJECTIVES In the Emirate of Dubai, a vaccination experiment was carried out with an inactivated AHS vaccine produced at the Central Veterinary Research Laboratory (CVRL), Dubai, UAE to investigate the humoral antibody response of AHS-naive horses to this vaccine. Our vaccination experiment was performed to establish an AHS vaccine bank in the UAE to protect horses from the disease in case of an outbreak. Therefore, CVRL established an inactivated AHS vaccine containing all nine serotypes which induce high neutralising antibodies. STUDY DESIGN A total of 10 horses kept in a desert isolation area were subcutaneously and intramuscularly vaccinated with an inactivated vaccine containing all nine AHS serotypes previously isolated from Kenyan horse fatalities. Primary immunisation was followed by two booster immunisations 4 weeks and 6 months apart. After 13 months, an annual booster was administered. METHODS Blood samples were regularly withdrawn for ELISA and virus neutralisation testing. Additionally, EDTA blood was tested every second day for 14 days post each vaccination for the presence of AHS virus or its RNA. RESULTS Results show that ELISA and virus neutralising antibodies appeared after the first booster, declined after 4-6 months and therefore three vaccinations and an annual vaccination are necessary to achieve high protective virus neutralising antibodies. MAIN LIMITATIONS No challenge infection was carried out due to the lack of a safe facility in the UAE. CONCLUSION Before more advanced AHS vaccines become a reality, inactivated vaccines containing all nine serotypes should be used as they produce high ELISA and neutralising antibodies.

A novel inactivated vaccine, comprising three serovars of Salmonella enterica (Enteritidis, serogroup O:9; Typhimurium, serogroup O:4; Infantis, serogroup O:7) grown under conditions of iron restriction and adjuvanted with aluminium hydroxide, was evaluated for efficacy following challenge by homologous and heterologous serovars. Chickens were vaccinated at 6 and 10 weeks of age by the intramuscular route and challenged 4 to 9 weeks after the second vaccination with serovars belonging to serogroup O:9 (Enteritidis), O:4 (Typhimurium and Heidelberg), O:7 (Infantis and Virchow), and O:8 (Hadar). All vaccinated birds produced a marked systemic antibody response against each of the component vaccine antigens by the time of challenge. Significant reductions in both colonization of the intestinal tract and invasion of internal organs were observed in vaccinated birds compared with non-vaccinated controls, irrespective of the challenge serovar. The findings suggest that broad serovar protection within the constitutive serogroups of an inactivated multi-valent vaccine is possible and could, therefore, play an important role in future Salmonella control programmes. RESEARCH HIGHLIGHTS Novel inactivated trivalent Salmonella chicken vaccine was developed and tested. Vaccine induced marked systemic antibody response against all vaccine antigens. Significant reductions in intestinal tract colonization and internal organ invasion. Vaccine efficacy demonstrated against homologous and heterologous serovars.

Background The efficacy of a novel inactivated intradermal Lawsonia intracellularis vaccine, Porcilis® Lawsonia ID, was evaluated in two experimental vaccination-challenge studies and under field conditions on a farm with a history of recurrent acute ileitis. In addition, the efficacy of the vaccine was compared to that of a commercially available live attenuated vaccine. The novel inactivated vaccine consists of a freeze-dried antigen fraction that is dissolved just prior to use in either the adjuvant or in Porcilis® PCV ID; an existing intradermal vaccine against porcine Circovirus type 2. In the two experimental vaccination-challenge studies, groups of 25 piglets were vaccinated once at 3 weeks of age or left unvaccinated as challenge control. Vaccines tested were Porcilis® Lawsonia ID as standalone (study 1) or in associated mixed use with Porcilis® PCV ID (study 2) and an orally administered commercially available live vaccine (study 1). The pigs were challenged with virulent L. intracellularis at 4 weeks (study 1) or 21 weeks (study 2) after vaccination. Post-challenge, the pigs were evaluated for clinical signs, average daily weight gain, shedding and macroscopic as well as microscopic immuno-histological ileum lesion scores. In the field study, the mortality and key performance parameters were evaluated over a period of 8 months. Results The results of the two experimental vaccination-challenge studies showed that Porcilis® Lawsonia ID as single vaccine or in associated mixed use with Porcilis® PCV ID, induced statistically significant protection against experimental L. intracellularis infection, 4 weeks or 21 weeks after vaccination. This was demonstrated by lower clinical scores, improved weight gain, reduction of L. intracellularis shedding and reduction of macroscopic as well as microscopic ileum lesion scores when compared to the controls. The protection induced was superior to that of the commercially available live vaccine. In the field study Porcilis® Lawsonia ID was highly efficacious in reducing L. intracellularis associated mortality and improving key production parameters. Conclusion The results support that this new intradermal vaccine is efficacious against L. intracellularis and may be used in associated mixed use with Porcilis® PCV ID.

Background Transmissible gastroenteritis virus (TGEV) causes enteric infection in piglets, characterized by vomiting, severe diarrhea and dehydration, and the mortality in suckling piglets is often high up to 100%. Vaccination is an effective measure to control the disease caused by TGEV. Methods In this study, cell-cultured TGEV HN-2012 strain was inactivated by formaldehyde (FA), β-propiolactone (BPL) or binaryethylenimine (BEI), respectively. Then the inactivated TGEV vaccine was prepared with freund's adjuvant, and the immunization effects were evaluated in mice. The TGEV-specific IgG level was detected by ELISA. The positive rates of CD4+, CD8+, CD4+IFN-γ+, CD4+IL-4+ T lymphocytes were detected by flow cytometry assay. Lymphocyte proliferation assay and gross pathology and histopathology examination were also performed to assess the three different inactivating reagents in formulating TGEV vaccine. Results The results showed that the TGEV-specific IgG level in FA group (n = 17) was earlier and stronger, while the BEI group produced much longer-term IgG level. The lymphocyte proliferation test demonstrated that the BEI group had a stronger ability to induce spleen lymphocyte proliferation. The positive rates of CD4+ and CD8+ T lymphocyte subsets of peripheral blood lymphocyte in BEI group was higher than that in FA group and BPL groups by flow cytometry assay. The positive rate of CD4+IFN-γ+ T lymphocyte subset was the highest in the BPL group, and the positive rate of CD4+IL-4+ T lymphocyte subset was the highest in the FA group. There were no obvious pathological changes in the vaccinated mice and the control group after the macroscopic and histopathological examination. Conclusions These results indicated that all the three experimental groups could induce cellular and humoral immunity, and the FA group had the best humoral immunity effect, while the BEI group showed its excellent cellular immunity effect.

Introduction. The only currently available live vaccine against yellow fever (YF) based on chicken embryos infected with an attenuated 17D strain of the YF virus is one of the most effective vaccine preparations. However, the live vaccine is associated with “viscerotropic syndrome” (approximately 0.4 cases per 100 000 vaccinated). Therefore, the development and introduction of highly purified inactivated vaccine against YF is intended to ensure the maximum safety of vaccination against one of the most common human viral diseases. Goals and objectives . Development and evaluation of immunogenicity of the cultural inactivated vaccine against YF at the laboratory model level. Material and methods. Adaptation of 17D strain of YF virus to Vero cell culture, cultivation, removal of cellular DNA, inactivation with β-propiolactone, concentration, chromatographic purification, determination of protein and antigen of YF virus, assessment of immunogenicity in mice in parallel with commercial live vaccine. Results and discussion . Immunogenicity: the determination of specific antibodies of class G (IgG) and virus neutralizing antibodies in the sera of immunized mice showed high level of antibodies exceeding that of immunized with commercial live vaccine. The optimal dose of antigen in the vaccine (total protein) was 50 μg/ml (5 μg/0.1 ml -dose and volume per 1 vaccination of mice). Thus, the laboratory version of cultural inactivated vaccine against YF is as effective (and even superior) as the commercial live vaccine. Conclusion. Laboratory version of cultural inactivated vaccine against YF, which is not inferior in immunogenicity (in animal model) to commercial live vaccine, has been developed.

Even massive vaccination programs, the incidence of Newcastle Disease virus (NDV) outbreaks in Egypt is still frequent with appearing new isolates that need production of new vaccines. In this study, NDV vaccine was prepared by using a new local isolate (NDV/Ch/Giza2014) inactivated by two different chemicals binary ethylenimine (BEI) and formaldehyde. The formaldehyde inactivated NDV (NDVF), BEI inactivated NDV (NDVEI) and imported inactivated Newcastle Disease virus (NDVI) vaccines were examined for generating humoral immune response in different groups of specific pathogen free (SPF) chicks. Vaccinated Chicks by NDVEI vaccine gave higher serum antibody titers than NDVF and NDVI Vaccines using Haemagglutination Inhibition (HI) test. The prepared and imported vaccines gave near percentage of protection against the local and the classical strain in chicks. It could be concluded that the locally prepared inactivated NDV vaccines can protect chicken against either homologous or heterologous challenging viruses and the NDVEI Vaccine gave higher protection percentage than NDVF and NDVI Vaccines.

The H9N2 avian influenza virus has been widely spread in poultry around the world. It is proved to the world that the avian influenza virus can directly infect human beings without any intermediate host adaptation in “1997 Hong Kong avian influenza case,” which shows that the avian influenza virus not only causes significant losses to the poultry industry but also affects human health. In this study, we aimed to address the problem of low protection of avian H9N2 subtype influenza virus vaccine against H9N2 wild-type virus. We have rescued the H9.4.2.5 branched avian influenza virus isolated in South China by reverse genetics technology. We have recombined these virus (rHA/NA-GD37 and rHA/NA-GD38) which contain hemagglutinin and neuraminidase genes from the H9N2 avian influenza virus (MN064850 or MN064851) and 6 internal genes from the avian influenza virus (KY785906). We compared the biological properties of the virus for example virus proliferation, virus elution, thermostability, and pH stability. Then, we evaluated the immune effects between rHA/NA-GD37 and GD37, which show that the recombinant avian influenza virus–inactivated vaccine can stimulate chickens to produce higher antibody titers and produce little inflammatory response after the challenge. It is noticeable that the recombinant virus-inactivated vaccine had better immune impact than the wild-type inactivated vaccine. Generally speaking, this study provides a new virus strain for the development of a H9N2 vaccine.

We developed an H5/H7 trivalent inactivated vaccine by using Re-11, Re-12, and H7-Re2 vaccine seed viruses, which were generated by reverse genetics and derived their HA genes from A/duck/Guizhou/S4184/2017(H5N6) (DK/GZ/S4184/17) (a clade 2.3.4.4d virus), A/chicken/Liaoning/SD007/2017(H5N1) (CK/LN/SD007/17) (a clade 2.3.2.1d virus), and A/chicken/Guangxi/SD098/2017(H7N9) (CK/GX/SD098/17), respectively. The protective efficacy of this novel vaccine and that of the recently used H5/H7 bivalent inactivated vaccine against different H5 and H7N9 viruses was evaluated in chickens. We found that the H5/H7 bivalent vaccine provided solid protection against the H7N9 virus CK/GX/SD098/17, but only 50–60% protection against different H5 viruses. In contrast, the novel H5/H7 trivalent vaccine provided complete protection against the H5 and H7 viruses tested. Our study underscores the importance of timely updating of vaccines for avian influenza control.

The incidence of Newcastle Disease virus (NDV) outbreaks in Egypt is still frequent even massive vaccination programs that due to viral mutation and appearing new isolates that need new vaccination program. Inactivated Newcastle Disease virus (NDV) vaccine was prepared using a new local isolate (NDV/Ch/Giza2014), from Giza governorate, Egypt, inactivated with binary ethylenimine (BEI) and emulsified with Montanide ISA70VG as an oil adjuvant. The prepared vaccine was evaluated in comparison with an inactivated imported vaccine. Chick groups vaccinated with either prepared or imported vaccines showed high serum antibody titers from the third week post vaccination until reached the maximum titer at the 9th week post vaccination using Haemagglutination Inhibition (HI) test. The prepared and imported vaccines gave 95-100% of protection against the local and the classical strain in chicks, during challenge period, there no clinical signs or lesions on examination. Our Conclusion that the locally prepared inactivated NDV vaccine can protect chicken against either homologous or heterologous challenging viruses.

The purpose of the study was to analyze the effectiveness of the adjuvant complex based on saponin, glycerin and chitosan in the experimental series of an inactivated vaccine against cattle necrobacteriosis. 4 groups of animals (30 in each group) were selected for the study, aged 6 to 24 months. The first (1st) group consisted of calves 6 months old, the second (2nd) group consisted of animals 12 months old and the third group – animals 24 months old. The control 4 (fourth) group (non-vaccinated animals) contained 10 animals of each age group – 6, 12 and 24 months old. The animals were vaccinated using a needle-free injector at a dose of 0.4 cm3 in two points at a distance of 7–10 cm (0.2 cm3 each) twice at intervals of 4-6 weeks. Revaccinated after 6 months, with a single dose of 0.4 cm3 (at two points, 0.2 cm2 each). It was found that the vaccine with the multicomponent adjuvant had low viscosity and hardening temperature, moderate reactivity, high stability during storage, prolonged immunity in vaccinated animals. The immunity in animals was detected 21 days after the first vaccine administration and lasted at least 18 months after the last immunization. The necrobacteriosis incidence in animals of the control non-vaccinated group was 70-80%. During double vaccination, the average level of postvaccinal agglutinating antibodies in serum of experimental groups of animals was 312.08±74.12 – 62.13±69, 07. Humoral response in vaccinated animals provided reliable protection against Fusobacterium necrophorum disease within two years (observation period). Absence of disease symptoms in vaccinated animals during 2 years testified to the high preventive efficiency of the vaccine. The results obtained confirm the validity of the application of multicomponent adjuvant in inactivated sorbed vaccine as a means of specific prevention of animal necrobacteriosis.

Inactivated influenza vaccines are known to be less immunogenic in human elderly in regards to serologic antibody response induced by vaccination. Accumulating evidence, however, points to a comparable effectiveness of influenza vaccines in the young and the elderly individuals. In the current study, we assessed immunogenicity and effectiveness of trivalent inactivated vaccine FluLaval in young and aged cotton rats Sigmodon hispidus and found that while serologic response to immunization was indeed reduced in older animals, comparable protection against influenza infection was afforded by prime-boost vaccination in both young and aged cotton rats. Both hemagglutination inhibition (HAI) titers and seroconversion rates were lower in the aged animals compared to the young ones. Reduction of viral load in the lung and nose, however, was comparable between young and aged animals vaccinated twice. One-time immunization with FluLaval was less efficacious at protecting the nose of aged animals, indicating that boosting of preexisting immunity can be particularly important for nasal protection in the elderly. Coincidentally, a one-time immunization with FluLaval had a detrimental effect on pulmonary pathology in the young animals, suggesting that boosting of immunity is essential for the young as well. Overall, these results suggest that reduced antibody response to and sufficient efficacy of influenza vaccines in the elderly are not two irreconcilable phenomena and that incomplete immunity to influenza can be detrimental at any age.

The anaerobic pathogen Clostridium perfringens is the most potent cause of intestinal diseases, such as enterotoxemia, hemorrhagic enteritis, and lamb dysentery, in sheep. Three toxinotypes (B, C, and D) are usually the cause of these diseases and are mainly mediated via three important exotoxins: alpha toxin (CPA), beta toxin (CPB), and epsilon toxin (ETX). We have designed a chimeric protein, rCpa-b-x, that contains the C-terminal binding region of CPA, partial sequence of CPB, and ETX (Cpa247-370, Cpb108-305, and EtxH118P, respectively) according to the principle of structural vaccinology. The rCpa-b-x protein was then expressed by pHT43 plasmid in vivo using Bacillus subtilis as a delivery vector (Bs-pHT43-Cpa-b-x). The immunological activity of the rCpa-b-x protein was verified by western blot and its immunological efficacy was evaluated in a murine model. Oral administration with a recombinant agent caused local mucosal and systemic immune responses, and serum lgG and intestinal mucosal secretory IgA (sIgA) antibody titers were significantly increased. Levels of IL-2, IL-4, and IFN-γ were significantly higher in lymphocytes isolated from the Bs-pHT43-Cpa-b-x group compared with levels from the control groups. The percentages of CD4+ and CD8+ T lymphocytes in the Bs-pHT43-Cpa-b-x and inactivated vaccine (IV) groups were in the normal range. Mice of vaccine groups and control groups were challenged with 1x LD100 unit filtrate containing alpha, beta, and epsilon toxins. Mice in the Bs-pHT43-Cpa-b-x group were found to have lower rates of morbidity. The active immunization of mice with Bs-pHT43-Cpa-b-x still maintained 85% to 90% survival at the end of the 10-day observation period, whereas mice of control groups died within two to five days. The results of this study demonstrate the effectiveness of Bs-pHT43-Cpa-b-x in preventing C. perfringens infection in mice, and that Bs-pHT43-Cpa-b-x could be considered a potential vaccine against C. perfringens.

Foot and mouth disease virus (FMDV) is a highly contagious pathogen propagating among cloven-hoofed animals. As a major immunogenic protein, VP1 plays a pivotal role in the induction of neutralizing antibodies, which therefore is an ideal target for developing subunit vaccines. In current study, four prokaryotic expression clones (rV4C, rC4V, rV5F and rF5V) were constructed by fusing truncated calreticulin (CRT) (120–250 aa or 120–308 aa) at the N/C terminal of vp1 gene, and co-expressed with chaperone trigger factor 16 (Tf16) in E.coli, respectively. The soluble recombinant CRT-fused VP1 proteins could form into homogeneous reactive polymers with average hydrodynamic diameters around 100 nm according to the dynamic light scattering (DLS) data. Immunization of guinea pigs with 10 μg purified CRT-fused VP1 proteins induced high levels of antibodies against naked-VP1 through indirect ELISA. Sandwich ELISA showed that only rC4V could elicit the same level of antibody against FMD virus as commercial inactivated vaccine after booster. The lymphocyte cytokines secretion of immunized rC4V was higher than the other CRT-fused VP1 proteins in guinea pigs. These results showed that the soluble CRT-fused VP1 proteins, especially rC4V, expressed with Tf16 in E. coli might have potential to be used as subunit vaccine candidate against FMDV.

Foot-and-mouth disease (FMD) is an acute, febrile, and highly contagious infectious disease common in cloven-hoofed animals. Outbreaks and epidemics of FMD can result in major economic losses of livestock. Using ferritin nanoparticles as the scaffold for an antigen can enhance the immunogenicity of the subunit vaccine and provide possible protection against FMD. We used a baculovirus expression system to express four recombinant proteins (VP1, VP1-Ft, G-H loop-Ft, and ferritin) and the protective immunity of the FMD ferritin nanoparticle vaccines was evaluated in mice. The recombinant subunit vaccines containing VP1, VP1-Ft, and G-H loop-Ft proteins significantly increased FMDV-specific IgG and IgG subclass antibody titers compared with the PBS group, as well as enhancing splenocyte proliferation and the expression of IL-4 and IFN-γ. The VP1 and VP1-Ft vaccines provided survival rates of 55.6% and 66.7%, respectively. The G-H loop-Ft vaccine provided a 77.8% survival rate compared with 100% survival in the inactivated vaccine group. The partial survival provided by the ferritin nanoparticle vaccines indicated that further study of the effects of the fused ferritin nanoparticle FMDV vaccines in animals is warranted.

In a trail to improve rabies vaccine's immunogenicity, water-soluble acrylic acid (carbopol) was used as an adjuvant in the prepared vaccine. The potency test of the National Institute of Health revealed that the prepared vaccine is potent and efficient. Studying the dynamics of serum antibody in vaccinated dogs using serum neutralizing antibodies test and ELISA showed that antibody titer (0.9 and 1.2352 respectively) reached a level considered protective within two weeks and increased till lasted consist ant (2.4 and 2.694) during the experiment for about twenty-four weeks. In conclusion, the present study results indicated that the vaccine formulated according to this study procedure could provoke long-lasting protective immune response after a single dose administration without any adverse reaction.

Made available in DSpace on 2020-12-12T02:01:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Aeromonas hydrophila is responsible for outbreaks of a severe infectious disease in fish farms around the world and is one of the major causes of economic losses to the neotropical fish farmers. This study assessed the induction of immune responses and protection against A. hydrophila in pacu, Piaractus mesopotamicus, vaccinated through intraperitoneal and immersion route with inactivated virulent strain. Fish were randomly distributed in three vaccinated groups: intraperitoneal (i.p.) route; immersion; and immersion + booster; and control group (unvaccinated). All vaccination protocols used the concentration of 1.7 × 108 CFU mL−1 of inactivated A. hydrophila., and an oil adjuvant was used for vaccine prepararion for i.p. route vaccination. Blood and skin mucus from 9 fishes per treatment were collected at 14, 28, 42 and 84 days post-vaccination (DPV) for determination of lysozyme concentration in skin mucus, as well as antibodies anti-A. hydrophila in blood serum and skin mucus. Fish were challenged at 84 DPV with homologous and virulent strain of A. hydrophila for evaluation of resistance against bacterial infection. The results demonstrated that vaccination with inactivated A. hydrophila suspension by i.p. or immersion resulted in significant increase of skin mucus lysozyme and specific antibody levels in serum and skin mucus, at 28 and 42 DPV, and this increase in innate and adaptive immunity remained significant in pacu vaccinated through i.p. route up to 84 DPV. Although no significant differences were observed in the survival study, pacu vaccinated through i.p. route presented 31,33% of relative percentage survival (RPS) in LD50–96h when compared unvaccinated fish challenged at 84 DPV. The results observed in this study indicate that vaccination programs with inactivated A. hydrophila, including booster doses by i.p. or immersion routes, could result in more effective protection in pacu against this bacteriosis, by increasing innate and adaptive mucosal and systemic immune responses. Laboratory of Aquatic Organisms Pathology (Lapoa) Aquaculture Center from UNESP (CAUNESP), Rodovia de Acesso Paulo Donato Castellane s/n Department of Microbiology Faculty of Sciences University of Malaga Department of Preventive Veterinary Medicine São Paulo State University (Unesp), Rodovia de Acesso Paulo Donato Castellane s/n, Zona Rural Department of Microbiology São Paulo State University (Unesp), Rodovia de Acesso Paulo Donato Castellane s/n, Zona Rural Laboratory of Animal Pharmacology and Toxicology Brazil University, Av. Hilário da Silva Passos, 950 Laboratory of Aquatic Organisms Pathology (Lapoa) Aquaculture Center from UNESP (CAUNESP), Rodovia de Acesso Paulo Donato Castellane s/n Department of Preventive Veterinary Medicine São Paulo State University (Unesp), Rodovia de Acesso Paulo Donato Castellane s/n, Zona Rural Department of Microbiology São Paulo State University (Unesp), Rodovia de Acesso Paulo Donato Castellane s/n, Zona Rural FAPESP: 2012/12256-7 CNPq: 432830/2016-2

Enterovirus D68 (EV-D68) infection may cause severe respiratory system manifestations in pediatric populations. Because of the lack of an effective preventive vaccine or specific therapeutic drug for this infection, the development of EV-D68-specific vaccines and antibodies has become increasingly important. In this study, we prepared an experimental EV-D68 vaccine inactivated by formaldehyde and found that the serum of rhesus macaques immunized with the inactivated EV-D68 vaccine exhibited potent neutralizing activity against EV-D68 virus in vitro. Subsequently, the antibody-mediated immune response of B cells elicited by the inactivated vaccine was evaluated in a rhesus monkey model. The binding activity, in vitro neutralization activity, and sequence properties of 28 paired antibodies from the rhesus macaques' EV-D68-specific single memory B cells were analyzed, and the EV-D68 VP1-specific antibody group was found to be the main constituent in vivo. Intriguingly, we also found a synergistic effect among the E15, E18 and E20 monoclonal antibodies from the rhesus macaques. Furthermore, we demonstrated the protective efficacy of maternal antibodies in suckling C57BL/6 mice. This study provides valuable information for the future development of EV-D68 vaccines.

Approximately 10,000 cases of tick-borne encephalitis (TBE), a serious disease of the central nervous system caused by tick-borne encephalitis virus (TBEV), are registered worldwide every year. Vaccination against TBE remains the most essential measure of preventing the disease. Unlike available TBE vaccines, a new inactivated lyophilized candidate vaccine Evervac is produced in Vero continuous cell culture and its final formulation does not include aluminum-based adjuvants. To study the safety and immunogenicity of Evervac, healthy adults 18–60 y of age were immunized twice at 30-d intervals. The study was single-blind, randomized, comparative, controlled, and was conducted in TBE-endemic areas. The commercial lyophilized vaccine TBE-Moscow was used as a comparison treatment. The subjects were observed for incidence, severity, and duration of adverse reactions. It was shown that the severity of local and systemic reactions in the Evervac vaccine group was mild to moderate. There were no significant differences in the incidence of adverse reactions between the Evervac and TBE-Moscow vaccine groups. Immunization with Evervac produced a significant increase in geometric mean titer (GMT) of anti-TBEV antibodies in both initially seronegative and seropositive recipients. The seroconversion rate for the initially seronegative recipients was 69% (GMT = 1:214) after the first dose and reached 100% after the second dose. In these parameters, there were no significant differences between the study and control vaccine groups. Thus, the adjuvant-free Vero-based vaccine Evervac was well tolerated, had low reactogenicity, induced a pronounced immune response, and was overall non-inferior to the commercial adjuvanted TBE vaccine used as a control.

Enterococcus cecorum (EC) is known to cause skeletal lesions in broiler chickens and also systemic infections in Pekin ducks. Despite the importance of the pathogen, there is still a lack of serological diagnostic tools for the detection of EC infections. Here we describe the development of an in-house indirect enzyme-linked immunosorbent assay (ELISA) for the detection of EC-specific antibodies and its application by examination of 67 sera from experimentally infected Pekin ducks, 710 field samples from four Pekin duck breeder flocks previously vaccinated with inactivated vaccines, and 80 samples from commercial Pekin ducks coming from vaccinated parent flocks. All groups that had been experimentally inoculated via the air sac route were positive in the new ELISA, with significantly (P ≤ 0.05) increased mean sample/positive (S/P) ratios of 0.71-2.70 at days 7, 14 and 21 post-infection, while orally inoculated ducks and the EC-free control group remained negative with mean S/P ratios of 0.0-0.15. Antibodies were also detected in each of four vaccinated Pekin duck breeder flocks; 67.8% of the samples were antibody positive. The highest S/P ratios were found between 16 and 26 weeks (median S/P ratios from 0.15 to 1.03), but antibodies were still detected in some serum samples in weeks 61-67 post-hatch. No antibodies were detected in the commercial Pekin ducks. Antibody development in the ducks may be influenced by the composition of the inactivated vaccine. The new ELISA provides a useful tool for investigations of response to EC infections and vaccinations.

Objective Development of an effective mucosal vaccine to induce specific immune responses against Foot-and-mouth disease virus (FMDV). Results For this purpose, the FMDV VP1 gene (SPVP1) was optimized and synthesized based on the codon bias of Lactococcus lactis (L. lactis), and then incorporated in the plasmid pNZ8148. L. lactis NZ9000 containing the pNZ8148-SPVP1 recombinant plasmid was used as an oral delivery vehicle to induce anti-FMDV mucosal and systemic immune responses in mice. After confirmation that the SPVP1 protein was expressed successfully in the recombinant L. latic, the mice were orally challenged with NZ9000-pNZ8148, NZ9000-pNZ8148-SPVP1, phosphate-buffered saline as a mock infection group, or with inactivated vaccine as a positive group. Mice immunized with NZ9000-pNZ8148-SPVP1 produced high levels of mucosal secretory IgA (sIgA), antigen-specific serum IgG, IgA, and neutralizing antibodies, and developed stronger cell-mediated immune reactions and significant T spleen lymphocyte proliferation. Furthermore, the recombinant group generated much higher levels of IFN-γ, IL-2, IL-4, IL-5, and IL-10 than the other groups. Conclusions Potent immune responses were successfully elicited in mice with FMDV VP1 delivered through L. lactis.