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Cyclic lipopeptides such as surfactin and polymyxin have potent mucosal adjuvant properties. Cyclic lipopeptides are tensioactive compounds, but the relationship between adjuvanticity and surface activity is unknown. Here, we show that the critical micelle concentration (cmc) of surfactant and particle size of the surfactant- protein complex are important determinants of cyclic lipopeptide adjuvanticity. We found that the diameter of cyclic lipopeptide -ovalbumin (OVA) complex particles was significantly larger than that in the solutions of OVA alone at cyclic lipopeptide concentrations above the cmc. OVA -specific antibody titres in mice immunized intranasally with OVA and a cyclic lipopeptide at concentrations above its cmc were significantly higher than those in mice immunized with OVA plus the same dose of the cyclic lipopeptide but administered with formulations in which cyclic lipopeptide concentration was below the cmc. Thus, the concentration of the cyclic lipopeptide in the formulation at immunization, but not its overall dose, was critical for its adjuvanticity. Furthermore, two types of aggregates, the cyclic lipopeptide simplex micelles and the cyclic lipopeptide -OVA complex micelles, were found in formulations with SF concentrations above its cmc. Degranulation of mast cells exposed to SF simplex micelles was more pronounced when SF concentration was above the cmc. In conclusion, our study showed that surface activity properties, such as the cmc and the size of surfactant -protein complex, contribute to the adjuvanticity of cyclic lipopeptides. Our study proposes a novel idea that cmc is a key parameter for tensioactive adjuvants. [ABSTRACT FROM AUTHOR]

Abstract: DNA vaccination is a promising cancer treatment due to its safety, but poor immunogenicity limits its application. However, immunoadjuvants, heterogeneous prime‐boost strategies and combination with conventional treatments can be used to improve the antitumour immune effects. A CpG motif and interleukin‐2 (IL‐2) cytokine are often used as adjuvants. In this study, a DNA vaccine containing a CpG motif was constructed to evaluate its adjuvant effect. The results show that the cytotoxicity of the DNA vaccine was increased fivefold, and survival lifetime was prolonged twofold by the CpG motif adjuvant. To simplify the industrial production process, a bicistronic plasmid was constructed to carry the fusion genes of survivin/MUC1 (MS) and IL‐2 and with a CpG motif in its backbone. The results showed that the antitumour effect of the bicistronic vaccine was the same as that of the two vaccine co‐injected regime. Furthermore, the vaccine could suppress metastatic tumour foci by 69.1% in colorectal carcinoma‐bearing mice. Moreover, the vaccine induced survivin‐ and MUC1‐specific immune responses in splenocytes and induced the immune promoting factor CCL‐19 and GM‐CSF upregulated, while metastatic‐associated factor MMP‐9 and immunosuppressing factor PD‐L1 downregulated in tumour tissue. When combining the vaccine with the chemotherapy drug oxaliplatin, the survival was prolonged by about 2.5‐fold. In conclusion, the DNA vaccine containing a CpG motif in bicistronic form showed good effects on colorectal cancer by inhibiting both tumour growth and metastasis, and combination with oxaliplatin could improve its antitumour effects. [ABSTRACT FROM AUTHOR]

Autoimmune diseases are pathological conditions characterized by abnormal responses, accompanied by autoantibodies to self-molecules. The role of vitamin D in autoimmune diseases has increased significantly in the recent past from its functions in calcium and phosphate homoeostasis, and it is now involved in the regulations and proliferations of Th1 and Th17 lymphocyte. 1α,25(OH)2D3 is very important in ameliorations of inflammatory disorders arising from autoimmune diseases, but the mechanism by which this is performed is still a bone of contentions. This review aimed to highlight the existing facts about the roles of Vitamin D in the treatment and management of autoimmune diseases. An extensive online literature search was conducted using PubMed, MEDLINE and Scopus. Accumulated bodies of research evidence are available which demonstrates that Vitamin D has a very important part to play in the regulation of immune responses in autoimmune diseases. Some of the authors suggested that Vitamin D3 carry-out its immunosuppressive and immune modulatory action, through its actions on antigen-presenting cells and activated T and B cells with the help of Vitamin D receptors present on the each of these cells. Vitamin D supplementation assists in autoimmune disorders by making qualitative and quantitative changes in the immune system (downregulation of Th1 and upregulations of Th2 cells). This resulted in the body to be more tolerant of self and less likely to mount autoimmune responses. [ABSTRACT FROM AUTHOR]

Myeloid-derived suppressor cell ( MDSC) is an important heterogeneous cell population that regulates innate and adaptive immune. The immunosuppressive potentiality is widely known. However, more and more data indicated that the heterogeneous cell population had immunostimulatory activities rather than immunosuppression in some microenvironments. Chronic inflammatory conditions contribute to accumulation of MDSCs. These pathologically activated cells played critical roles in cancer and inflammatory diseases. In this review, we mainly discuss the immunoregulation potentiality of MDSCs in cancer and inflammatory diseases. [ABSTRACT FROM AUTHOR]

The vitamin D analogue calcipotriol is an immunomodulatory drug widely used to treat psoriasis; however, how calcipotriol affects the immune cells in psoriasis lesions is not fully understood. The aim of this atudy was to investigate the effect of calcipotriol on the frequency of CD4+ and CD8+ T cells and innate lymphoid cells ( ILC) and their production of IL-17A, IFN- γ and IL-22 in psoriasis lesions in patients with chronic plaque psoriasis. Eighteen patients with psoriasis were included, and two similar psoriasis lesions were chosen for each patient. One lesion was treated with calcipotriol (50 μg/g) and the other with vehicle twice a day for 14 days. The clinical effect was measured by degree of erythema, scaling and induration in each lesion ( SUM score). Skin biopsies were collected for histological and immunohistochemical analyses. Skin-derived cells were isolated and analysed by flow cytometry. After 14 days of treatment with calcipotriol, a significant clinical and histological effect was seen; however, we found no differences in the frequency of CD4+ and CD8+ T cells or ILC between calcipotriol- and vehicle-treated skin. The main finding was a significant decrease in CD8+ IL-17+ T cells in skin-derived cells from calcipotriol-treated skin, which was further supported by the absence of CD8+ IL-17+ T cells in immunohistochemical staining of calcipotriol-treated skin. No changes in the frequency of IL-22+ or IFN- γ+ cells were observed. Our findings show that the vitamin D analogue calcipotriol reduces the frequency of CD8+ IL-17+ T cells in psoriasis lesions concomitant with clinical improvement. [ABSTRACT FROM AUTHOR]

The enormous capacity of Staphylococcus aureus to acquire antibiotic resistance makes it a permanent task to search for and to develop new anti-infectives. One of the possible approaches is the early active immunization of risk patients and animal stocks to prevent S. aureus infections. Based on a S. aureus proteome screen with S. aureus-specific human antiserum, we have previously identified several anchorless cell wall proteins to be used as novel vaccine candidates. To develop an efficient anti-S. aureus vaccine, the supplemented adjuvants Montanide TM ISA 71 VG and ISA 206 were compared tofreund's adjuvant in terms of handling, induction of cytokine profile, triggering antigen-specific immunoglobulin production of different IgG subclasses and provision of increased survival rates in our S. aureus sepsis mouse model. Immunization with ISA 71 VG in comparison with Freund's adjuvant induced slightly delayed but comparably strong increase of antigen-specific antibody titres and conferred protective effect against S. aureus challenge. In contrast using ISA 206 as adjuvant, significantly lower IgG titres and consequently, no protective effect against S. aureus infection were observed. Handling and tolerability of the Montanide is superior tofreund's adjuvant. MontanideTM ISA 71 VG can serve as an effective adjuvant replacement for Freund's adjuvant in research with a prospective usage in animal and human vaccines against bacterial pathogens. [ABSTRACT FROM AUTHOR]

For the immune modulatory drug fingolimod (FTY720), lymphocyte sequestration has been extensively studied and accepted as mode of action. Further, direct effects on immune cell signalling are incompletely understood. Herein, we used the parent drug and newly synthesized analogues to investigate their effects on dendritic cell (DC) calcium signalling and on Th1, Th2 and Th17 responses. DC calcium signalling was determined with a single cell-based confocal assay and IL-33/ST2-TIR Th2-like response with ST2-transduced EL4-6.1 thymoma cells. The Th1/Th17 responses were examined with a LPS/TLR-enhanced antigen presentation assay with OVA-TCRtg CD4 and CD8 spleen cells. Our results revealed a comparable influence of fingolimod and S1P on intracellular calcium level in DC, while an oxy-derivative of fingolimod exhibited an EC50 of 3.3 n m, being 14 times more potent than FTY720-P. The IL-33/ST2-TIR Th2-like response in ST2-EL4 cells was inhibited by fingolimod and analogues at varying degrees. Using the OVA-TCRtg LPS/TLR-enhanced spleen cell assay, we found that fingolimod inhibited both IL-17 and IFN- γ production. In contrast, fingolimod phosphate failed to decrease Th1 cytokines. Interestingly, the effects of the parent compound fingolimod were modulated by the PP2A inhibitor okadaic acid, thus suggesting PP2A as relevant intracellular target. These studies describe detailed immune-modulating properties of fingolimod, including interference with a prototypical Th2 response via IL-33/ST2-TIR. Moreover, differential effects of fingolimod versus its phosphorylated derivative on TLR-activated and antigen-dependent Th1 activation suggest PP2A as an additional target of fingolimod immune therapy. Together with the analogues tested, these data may guide the development of more specific fingolimod derivatives. [ABSTRACT FROM AUTHOR]

Filariasis caused by infectious parasitic nematodes has been identified as the second leading source of permanent and long-term disability in Sub-Saharan Africa, Asia and Latin America. Several vaccine candidates were identified from infective third-stage larvae (L3) which involves in the critical transition from arthropod to human. Hitherto studies of these antigens in combination with alum adjuvant have shown to elicit its characteristic Th2 responses. Inulin is a safe, non-toxic adjuvant that principally stimulates the innate immune response through the alternative complement pathway. In the present study, the immune response elicited by inulin and alum as adjuvants were compared with filarial antigens from different aetiological agents: secreted larval acidic protein 1 (SLAP1) from Onchocerca volvulus and venom allergen homologue (VAH) from Brugia malayi as single or as cocktail vaccines in mice model. The study revealed that inulin can induce better humoral response against these antigens than alum adjuvant. Antibody isotyping disclosed inulin's ability to elevate the levels of IgG2a and IgG3 antibodies which mediates in complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity (ADCC), respectively, in mice. Splenocyte analysis showed that T cells prestimulated with inulin have higher stimulation index (P < 0.05) than alum except for BmVAH antigen. In vitro ADCC assay showed that inulin formulation had induced higher cytotoxicity with filarial antigens (as single P < 0.01 and as cocktail P < 0.05, respectively) than alum. The results had confirmed the capability of inulin to deplete the levels of Treg and brought a balance in Th1/Th2 arms against filarial antigens in mice. [ABSTRACT FROM AUTHOR]

This study was undertaken to isolate active secondary metabolites from immunostimulatory Alcaligenes faecalis FY-3 and evaluate their activities using grass carp Ctenopharyngodon idella kidney (CIK) cells. By applying chromatography techniques and successive recrystallization, three purified metabolites were obtained and identified by spectral data (mass spectrometry and nuclear magnetic resonance) as: (1) phenylacetic acid, (2) p-hydroxyphenylacetylamide and (3) cyclo-(Gly-L-Pro). CIK cells were stimulated by different concentrations (1, 10 and 100 μg/ml) of the isolated compounds, and expression of MyD88, IL-1β, TNF-α, type I-IFN and IL-8 genes at different time points (2, 8 and 24 h) post-stimulation was quantified by real-time PCR. The known immunostimulatory agent lipopolysaccharide (LPS) was used as a positive control. To analyse whether these compounds are toxic to the cells, the methyl tetrazolium assay was employed to measure changes in cell viability. The obtained results revealed that transcribing level of MyD88, an important adaptor molecule in toll-like receptor signalling pathway, was augmented remarkably by all the three isolated compounds and LPS as early as 2-h exposure. These compounds also induced gene expression of cytokines such as IL-1β, TNF-α and type I-IFN. Under the experimental conditions, none of the test compounds is toxic to the CIK cells. These findings demonstrate that the immunostimulatory properties of the three metabolites [phenylacetic acid, p-hydroxyphenylacetylamide and cyclo-(Gly-L-Pro)] from A. faecalis FY-3 in CIK cells and highlight the potential of using these metabolites as immunostimulants in fish aquaculture. [ABSTRACT FROM AUTHOR]

Glatiramer acetate (GA) is an immunomodulatory drug approved for the treatment of clinically isolated syndrome (CIS) and relapsing/remitting multiple sclerosis (RRMS). As an antigen-based therapy, GA induces GA-specific antibodies in treated patients and animals. GA-specific antibodies do not neutralize therapeutic effects on relapses and disability. Rather, it has been suggested that GA-specific antibodies may be associated with improved clinical outcomes. We evaluated antibody responses in eight patients with RRMS treated with GA for 15 months and antibody responses in GA-treated C57BL/6 mice before and after induction of experimental autoimmune encephalomyelitis (EAE). There were no significant differences from pretreatment levels of total IgE or GA-specific IgE in patients with RRMS. Total IgG1, IgG3 and GA-specific IgG4 were significantly increased at 15 months of GA treatment. Antibody type and titre were not associated with clinical outcomes, i.e. expanded disability status scale (EDSS) score, disease burden on magnetic resonance images (MRI) or clinical relapses. In contrast, mice with EAE showed a marked increase in GA-specific IgE and GA-specific IgG1 antibody responses. GA-treated mice demonstrated improved clinical symptoms and lower mortality than untreated controls. Our results suggest that antibody responses to GA are heterogeneous among patients with RRMS, with no apparent association between antibody response and clinical outcomes. Clinical improvements in EAE-induced GA-treated mice suggest that GA-specific IgE and IgG1 may contribute to GA treatment effects in EAE. [ABSTRACT FROM AUTHOR]

A strain was isolated from a soil sample collected from Weihe river in Shaanxi province (108°03′E 34°14′N), which was identified as Alcaligenes faecalis by 16S rRNA analysis. A compound M showing potent immune activity was isolated from secondary metabolites of the strain through bioassay-guided isolation techniques. The structure of the compound M was elucidated using FT-IR, EI-MS, 1H NMR and 13C NMR spectra and identified as cyclo-(-Pro-Gly)5 which was first time reported as a natural product. We evaluated the immune effects of the cyclo-(-Pro-Gly)5 on the basis of serum lysozyme activity, bacterial agglutination titre assay, superoxide anion production and phagocytic activity assay, and they were found to be significantly increased by cyclo-(-Pro-Gly)5. The effects of cyclo-(-Pro-Gly)5 on immune-related gene expression were further investigated. The outcomes of real-time quantitative polymerase chain reaction (RQ-PCR) proved that the transcribing level of interleukin 6β (IL-6β) and inducible nitric oxide synthase 1β (iNOS-1β) mRNA in the blood leucocytes have been augmented by cyclo-(-Pro-Gly)5. The challenge experiment showed that crucian carp injected the cyclo-(-Pro-Gly)5 had significantly ( P < 0.05) lower cumulative mortality (13.0%) compared with the control (45.4%) after infection with live Aeromonas hydrophila. These results suggested that cyclo-(-Pro-Gly)5 is a possible immunostimulant and may strengthen the immune response and protect the heath status of crucian carp against A. hydrophila. [ABSTRACT FROM AUTHOR]

An immunomodulatory extract (AndoSan™) based on the medicinal mushroom Agaricus blazei Murill (AbM) has shown to reduce blood cytokine levels in healthy volunteers after 12 days' ingestion, pointing to an anti-inflammatory effect. The aim was to study whether AndoSan™ had similar effects on cytokines in patients with ulcerative colitis (UC) and Crohn's disease (CD). Calprotectin, a marker for inflammatory bowel disease (IBD), was also measured. Patients with CD ( n = 11) and with UC ( n = 10) consumed 60 ml/day of AndoSan™. Patient blood plasma was harvested before and after 6 h LPS (1 ng/ml) stimulation ex vivo. Plasma and faecal calprotectin levels were analysed using ELISA and 17 cytokines [IL-2, IFN-γ, IL-12 (Th1), IL-4, IL-5, IL-13 (Th2), IL-7, IL-17, IL-1β, IL-6, TNF-α, IL-8, MIP-1β, MCP-1, G-CSF, GM-CSF and IL-10] by multiplex assay. After 12 days' ingestion of AndoSan™, baseline plasma cytokine levels in UC was reduced for MCP-1 (40%) and in LPS-stimulated blood for MIP-1β (78%), IL-6 (44%), IL-1β (41%), IL-8 (30%), G-CSF (29%), MCP-1 (18%) and GM-CSF (17%). There were corresponding reductions in CD: IL-2 (100%), IL-17 (55%) and IL-8 (29%) and for IL-1β (35%), MIP-1β (30%), MCP-1 (22%), IL-8 (18%), IL-17 (17%) and G-CSF (14%), respectively. Baseline concentrations for the 17 cytokines in the UC and CD patient groups were largely similar. Faecal calprotectin was reduced in the UC group. Ingestion of an AbM-based medicinal mushroom by patients with IBD resulted in interesting anti-inflammatory effects as demonstrated by declined levels of pathogenic cytokines in blood and calprotectin in faeces. [ABSTRACT FROM AUTHOR]

Dendritic cells (DC) are an essential link between the innate and adaptive immune response. To become effective antigen-presenting cells DC need to undergo maturation, during which they up-regulate co-stimulatory molecules and produce cytokines. There is great interest in utilizing DC in vaccination regimes. Over recent years, Toll-like receptor (TLR) signalling has been recognized to be one of the major inducers of DC maturation. This study describes a mutant version of the TLR adaptor molecule MyD88 (termed MyD88lpr) as a novel adjuvant for vaccination regimes. MyD88lpr specifically activates DC by disrupting a DC intrinsic inhibitory mechanism, which is dependent on single immunoglobulin IL-1R-related. Moreover, MyD88lpr was able to induce an IgG2a-dominated response to a co-expressed antigen, suggesting Th1 immunity. However, when used as a vaccine adjuvant for Influenza nucleoprotein there was no significant difference in the lung viral titres during the infection. This study describes MyD88lpr as a potential adjuvant for vaccinations, which would be able to target DC specifically. [ABSTRACT FROM AUTHOR]

Cry1Ac protoxin from Bacillus thuringiensis is a potent mucosal immunogen and adjuvant. When delivered intranasally (i.n.) Cry1Ac elicits significant antibody response and is able to improve vaccination against Naegleria fowleri infection, but the functional effects occurring in nasal lymphocytes when this protein is administered alone have not been determined. Here, we investigated the effects of i.n. immunization with Cry1Ac on antibody production, lymphocyte activation and cytokine production in lymphocytes from nasal-associated lymphoid tissue (NALT) and nasal passages (NP). Our results show that i.n. immunization with Cry1Ac induced significant specific IgA and IgG cell responses, especially in NP. Besides, it increased the proportion of lymphocytes expressing the activation markers CD25 and CD69 in both nasal tissues, but differently. CD25 was increased in B cells along with CD4 and CD8 T cells from NALT and NP, while CD69 was increased in B cells from both tissues but only in CD4 T cells from NP. Finally, we found that Cry1Ac augmented especially a Th2 profile of cytokines, as the proportion of T cells that spontaneously produced IL-4, IL-5 and IL-10 was increased and this effect was higher in NP than in NALT. These data contribute to explain the potent immunogenicity of Cry1Ac via i.n. route. [ABSTRACT FROM AUTHOR]

We have shown that Cry1Ac protoxin from Bacillus thuringiensis is a potent mucosal and systemic immunogen with adjuvant properties. Interestingly, we have observed that Cry1Ac preferentially induces high specific IgG responses in intestinal fluid when it is intraperitoneally administered to mice; therefore, in the present study, we used this protocol, as a model to address the influence of systemic immunization on the induction of the intestinal IgG response. The data shown indicate that upon intraperitoneal immunization with Cry1Ac, significant intestinal specific IgG cell responses were produced in the lamina propria, accompanied by an increased frequency of intestinal IgG+ lymphocytes and epithelial cells containing IgG. Considering that FcRn is the receptor responsible for the transport of IgG in neonatal intestinal epithelia, but it is developmentally downregulated in the rodent intestine, we analysed whether upon intestinal IgG induction, FcRn mRNA expression was induced in intestinal epithelial cells, of adult mice. Whereas in intestinal epithelia of unimmunized adult mice FcRn mRNA was not detected, in Cry1Ac immunized mice it was expressed, although the level was lower in comparison with that found in neonatal epithelia. Then using flow cytometry and immunofluorescence we confirmed that the expression of the protein FcRn was induced in the intestines of adult immunized mice especially in the large intestine. Finally, we found that Cry1Ac also increased FcRn expression in isolated intestinal epithelial cells stimulated in vitro. The outcomes suggest that the expression of FcRn in intestinal epithelium might be reactivated upon immunization, and possibly facilitate IgG transport. [ABSTRACT FROM AUTHOR]

It has previously been shown that a ∼27 kDa serine protease of Schistosoma mansoni larvae, the cercarial elastase (CE), was a poor immunogen in as much as it failed to induce an antibody response. The CE has a critical role in enabling schistosome larvae to penetrate the skin of their definitive hosts, so the apparently poor immunogenicity of this enzyme is clearly of interest. To understand its lack of immunogenicity better and in particular to determine whether it is related to its proteolytic activity, we have measured antibody responses of mice to three different serine proteases. Groups of mice were immunized with porcine pancreatic trypsin (TRY), chymotrypsin (CHY) or elastase (ELA) and the resulting antibody response compared with antibody responses to two non-protease antigens, chicken egg albumin (OVA) and Schistosoma japonicum glutathione S-transferase (GST), all being administered with alum as an adjuvant. Of 12 mice that were injected five times at 14 day intervals with TRY, only one produced antibody reactive with this enzyme in ELISA. Immunizations with CHY or ELA induced somewhat better antibody responses than TRY, but the responses to the first and second injections of these two proteases nevertheless seemed comparatively lower than the responses to GST. Induction of antibody responses by OVA and GST was not affected when TRY was injected concomitantly. Thus, the antibody response to one of the serine proteases used in this study, mammalian trypsin, was anomalous. [ABSTRACT FROM AUTHOR]

The oral commensal bacterium Streptococcus gordonii has been gathering interest as a candidate live mucosal vaccine delivery vector. S. gordonii has been shown to be capable of activating antigen presenting immune cells in a manner which leads to their activation and maturation, yet the mechanism used by S. gordonii to do so is poorly understood. The aim of this work was to investigate the immunostimulatory components of S. gordonii in inducing murine dendritic cell (DC) activation and maturation. Lipoteichoic acid (LTA), lipoprotein (LP), peptidoglycan (PGN), and DNA were isolated from S. gordonii, and used to stimulate murine DC. Cytokine production and DC surface marker upregulation in response to the bacterial components was quantified by enzyme-linked immunosorbent assay and flow cytometry respectively. The results were contrasted against data obtained from DC derived from MyD88, TRIF [TIR(Toll/Interleukin-1 Receptor)-domain-containing adapter-inducing interferon-beta] or toll-like receptor-2 (TLR-2) knockout mice. The four S. gordonii bacterial components were found to differentially induce cytokine production and surface marker upregulation by murine DC. Activation of DC by both whole S. gordonii cells and the four bacterial components was abrogated in the absence of MyD88, but not in the absence of TRIF. LTA, LP and PGN, but not DNA and whole S. gordonii, required TLR-2 to induce a DC response. The results collectively indicate that S. gordonii activates DC predominantly through a MyD88-dependent and TRIF-independent pathway. This activation can be attributed to multiple immunostimulatory components present within S. gordonii bacterial cells. [ABSTRACT FROM AUTHOR]

IC31® is a novel adjuvant which combines the immunostimulatory effects of an 11-mer antibacterial peptide (KLKL5KLK) and a synthetic oligodeoxynucleotide (ODN1a) which is a Toll-like receptor 9 agonist without containing cytosine phosphate guanine (CpG) motifs. The effects of IC31® on neonatal immune response to vaccination have not been reported. Neonatal mice were immunized once or twice with a Streptococcus pneumoniae serotype 1 polysaccharide conjugate containing Tetanus Toxoid (Pnc1-TT) carrier protein, with or without IC31® or CpG-ODN. IC31® significantly enhanced IgG1, IgG2a and IgG2b antibodies (Ab) to the serotype 1 polysaccharide. One dose of Pnc1-TT and low dose IC31® elicited high Ab levels that protected the neonatal mice completely from bacteraemia and significantly reduced lung infection following i.n. challenge with serotype 1 pneumococcal strain. One-sixth of an adult murine dose of IC31® was sufficient and optimal for induction of protective immunity in neonatal mice. Two doses of Pnc1-TT with or without adjuvants protected the neonatal mice completely, but more rapid Ab response was observed when IC31® was given with the Pnc1-TT. IC31® is a promising new adjuvant for neonatal vaccinations, rapidly enhancing protective humoral responses when combined with Pnc1-TT. [ABSTRACT FROM AUTHOR]

T-cell mediated immune responses are key determinants to the natural course of infection caused by intracellular parasites such as Leishmania. Thus, T-cell activating proteins of these microbes continue to generate active interest particularly in view of their possible role in the design and development of newer and more effective vaccines. We have recently reported the presence of T-cell immunostimulatory antigens with the high-molecular-weight (MW) fractions (134–64.2 kDa) of whole Leishmania donovani antigen (strain 2001), which stimulated variable amounts of IFN-γ, IL-12 and IL-10 in exposed immune individuals. The present study was undertaken to further evaluate these high-MW antigenic fractions (MW range >100–60 kDa) for potential protective efficacy. The high-MW region of the parasite was resolved into five antigenic fractions (Prep A–E) using continuous elution gel electrophoresis. Prior to in vivo protection studies in hamsters, these fractions were used to evaluate in vitro cellular responses in eight Leishmania-exposed individuals and treated cured hamsters. The protective efficacy of prep (A + B), C, D and E in combination with BCG was evaluated in inbred hamsters using standard immunization protocol. Proliferative responses were seen in all eight of eight exposed individuals to prep D [median stimulation index (SI): 5.2 (range 3.9–7.1)] and E [median SI: 5.6 (range 4.4–8.2)], five of eight individuals to prep B and prep C and three of eight to prep A [median SI: 0.2 (range 0.1–7.2)]. The median proliferative responses to prep D and prep E were significantly higher than to fraction prep A; ( P < 0.05) but not to prep B and prep C. However, prep A–E induced equivalent levels of IFN-γ, IL-10 and IL-12 cytokines. Fractions D and E also exhibited marked parasite inhibition in spleen (52.5% and 73.7%) and liver (65% and 80.2%) as compared with prep (A + B) (23% in spleen and 24% in liver) and prep C (38% in spleen and 24% in liver). Prep D and prep E vaccinated animals showed higher in vitro stimulatory responses (mean SI: 6.6 and 8.8) and nitric oxide (NO) induction (mean NO levels: 6.4 and 10.7 μg/ml) against whole cell extract as compared with other groups. The protection also correlated with presence of suppressed Leishmania-specific IgG levels in prep D and prep E immunized hamsters. These studies indicate the presence of immunostimulatory and protective molecules in 60–80 kDa region of L. donovani, which may be further exploited for developing a subunit vaccine. [ABSTRACT FROM AUTHOR]

Many of the disorders today are based on the imbalances of immunological processes. This necessitates the search for newer and safer immunomodulators. Thus, the objective of the present study was to explore the immunomodulatory activity of the methanolic extract of Piper betel L. (MPb) (Family: Piperaceae). The MPb consists of mixture of phenols, flavonoids, tannins and polysaccharides. Both in vitro as well as in vivo evaluation was carried out. The effects of MPb on lymphocyte proliferation, interferon-γ receptors and the production of nitric oxide were measured in vitro. Further, the extract at different dose levels was studied in vivo for the humoral and cellular immune responses on mice immunized with sheep red blood cells. P. betel significantly suppressed phytohaemagglutinin stimulated peripheral blood lymphocyte proliferation in a dose-dependent manner. The decrease in antibody titre and increased suppression of inflammation suggests possible immunosuppressive effect of extract on cellular and humoral response in mice. Thus, the MPb could be explored extensively as a therapeutic agent to treat various immune disorders including autoimmune disorders. [ABSTRACT FROM AUTHOR]

The immune stimulation properties of CpG-oligonucleotides (CpG-ODN) containing a central unmethylated CpG motif could be useful for vaccination against parasite infection. However, the high cost of synthetic CpG-ODN has limited its use in veterinary vaccines. In this study, we investigated whether genomic DNA derived from Mycobacterium bovis bacillus Calmette–Guerin (BCG-DNA) could be used as an effective adjuvant to enhance the immunogenicity and the protective capacity of recombinant cC1 antigen (rcC1) against pig cysticercosis. Pigs were vaccinated with rcC1 plus CpG-containing DNA adjuvants (BCG-DNA or CpG-ODN) or rcC1 alone. Immunization with rcC1 alone induced a Th1-biased response, whereas coadministration of rcC1 with BCG-DNA or CpG-ODN increased levels of IgG2, IFN-γ, percentage of CD8+ and specific proliferation of peripheral blood mononuclear cells. Four weeks after the last immunization, pigs were infected with Taenia solium eggs. A high level of protection (81%) was induced by rcC1 immunization that was not significantly increased by the CpG-containing DNA. These data indicate that coadministration of rcC1 plus BCG-DNA or CpG-ODN significantly enhanced Th1 response but did not improve the level of the protection induced. [ABSTRACT FROM AUTHOR]

Leishmania mexicana is the main causal agent of cutaneous leishmaniasis in the Yucatán peninsula in Mexico. Control of this disease is associated with a Th1-type immune response and garlic extract has been reported as a Th1 immunomodulator in BALB/ c mice infected with Leishmania major. In this study, we investigated the effect of garlic extracts on L. mexicana infection in vivo and in vitro. Garlic extract reduced footpad lesions in L. mexicana-infected BALB/ c mice by inducing IFN-γ production from T cells. In vitro, garlic extract reduced macrophage infection through induction of nitric oxide (NO) production. Garlic extract may thus act on both T cells and macrophages to stimulate IFN-γ production and NO synthesis for parasite killing. A 10- to 14-kDa fraction was identified as responsible for the in vitro effect of the whole extract and may lead to the identification of novel immunomodulating drugs and therapeutic alternatives for the treatment of leishmaniasis. [ABSTRACT FROM AUTHOR]

The human cathelicidin LL-37 has been shown to be involved in the barrier function of the innate immunity, being released from specific cells upon challenge and exerting immunomodulatory effects. We here demonstrate that LL-37 affects immature dendritic cells, derived from human peripheral blood monocytes (MDDC). LL-37 is internalized by MDDC with subsequent localization primarily in the cytoplasmic compartment. However, LL-37 could also be detected in the nuclei of MDDC, suggesting that LL-37 may be transported into the nucleus. The uptake of LL-37 is dose, time and energy dependent, indicating that the observed internalization process involves an endocytic pathway. Incubation of immature MDDC with LL-37 caused phenotypic changes, characterized by an increased expression of the antigen-presenting molecule HLA-DR, and the costimulatory molecule CD86. Taken together, these findings suggest that LL-37 released upon triggering of the innate immunity, may affect cellular adaptive immunity through an interaction with immature dendritic cells. [ABSTRACT FROM AUTHOR]

Sixty-five healthy adult volunteers were immunized four times at 1-week intervals with an inactivated whole-virus influenza vaccine based on the strain A/New Caledonia/20/99 (H1N1) without adjuvant. The vaccine was administered as nasal spray with a newly developed device to secure intranasal delivery (OptiMist™, OptiNose AS, Oslo, Norway), as regular nasal spray, nasal drops or as an oral spray. Significant IgA-antibody responses in nasal secretions were induced in volunteers immunized intranasally but not after oral spray immunization. In saliva, IgA antibodies were only marginally amplified even after oral spray immunizations. At least 73% of the volunteers belonging to any group of vaccine delivery reached serum haemagglutination inhibition titres of 40 or higher, considered protective against influenza, after only two vaccine doses. Those who had the vaccine delivered intranasally also showed evidence from in vitro secretion of granzyme B that cytotoxic T cells had been stimulated. Although immunization with the breath-actuated OptiMist™ device and nasal drops were superior with respect to both mucosal and systemic immune responses, oral spray immunization might still be considered for studies of mucosal adjuvants that are not yet acceptable for intranasal use. [ABSTRACT FROM AUTHOR]

Safe and efficacious adjuvants are much needed to facilitate the development of mucosal vaccines. Here, we have asked whether our nontoxic vaccine adjuvant, CTA1-DD, can enhance protective immunity against Helicobacter pylori infection. Intranasal immunizations with H. pylori lysate together with CTA1-DD-adjuvant induced significant protection in C57Bl/6 mice, almost as strong as similar immunizations using cholera toxin (CT)-adjuvant. Protection remained strong even at 8 weeks postchallenge and the bacterial colonization was reduced by 20-fold compared to lysate-immunized controls. Although CTA1-DD was designed to bind to B cells, µMT mice developed significant, but lower, level of protection following immunization. Intranasal immunizations with CT adjuvant in C57Bl/6 mice resulted in the development of severe postimmunization gastritis at 2 and 8 weeks postchallenge, whereas the degree of gastritis was substantially lower in the CTA1-DD-immunized mice. Protection induced by both CTA1-DD- and CT adjuvant was associated with a strong local infiltration of CD4+ T cells in the gastric mucosa, and recall responses to specific Ag elicited substantial IFN-γ production, indicating Th1-dominance. These findings clearly demonstrate that CTA1-DD adjuvant is a promising candidate to be further exploited in the development of a mucosal vaccine against H. pylori infection. [ABSTRACT FROM AUTHOR]

We studied the effect of rolipram, a phosphodiesterase (PDE) IV inhibitor, on allergic footpad swelling in mice. For this study, varying adjuvants including complete Freund's adjuvant (CFA), incomplete Freund's adjuvant (IFA) and Imject Alum (Alum) were used because the extent of antigen-specifically induced T helper type 1 (Th1) and Th2 responses had been shown to depend on adjuvants used. To induce allergic footpad swelling, we immunized mice with ovalbumin (OVA) emulsified in either CFA or IFA, dissolved in Alum or in phosphate-buffered saline (PBS) as a control (day 0), followed by subcutaneous injection of the antigen into footpads on day 21. Rolipram was given orally to the animals daily from days 0–20. Results showed that treatment with rolipram was followed by an increase in early swelling at 0.5 h and a decrease in late swelling at 6 and 24 h in the CFA group. In the IFA group, rolipram significantly enhanced swelling at, but not after, 30 min. In the Alum and the PBS groups, the PDE inhibitor failed to affect the OVA-specific footpad reaction at all times examined. Treatment of the CFA and IFA groups with rolipram significantly inhibited the production of the Th1 antibody anti-OVA immunoglobulin G2a (IgG2a), and the drug enhanced Th2 cell-dependent anti-OVA IgE production. In both groups, rolipram also enhanced the secretion of Th2 cytokines including interleukin-4 (IL-4) and IL-10. These findings suggest that rolipram may facilitate early allergic footpad swelling mediated by Th2 immune responses, while the late phase of swelling associated with Th1 responses may be attenuated by the PDE IV inhibitor. [ABSTRACT FROM AUTHOR]

Mice immunized intranasally with a formalin-inactivated A/PR/8/34 (H1N1) influenza whole virus vaccine adjuvanted with cholera toxin, outer membrane vesicles from group B meningococci or formalin-inactivated whole cell Bordetella pertussis were protected against replication of the homologous virus in the nasal cavity. Only some mice were protected against clinical illness measured as weight loss and lowered body temperature. All mice immunized subcutaneously with one-tenth the intranasal vaccine dose without adjuvant were protected against clinical illness but not against local mucosal viral replication. Replicating virus was primarily found in animals with low concentrations of immunoglobulin (Ig)-A antibodies in saliva regardless of concentrations of IgG antibodies in serum. Clinical illness was seen only in those with low serum antibodies regardless of antibody levels in saliva. Nonreplicating nasal vaccines may not be sufficiently protective unless they also have a substantial influence on systemic immunity. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosiscan not only neutralize immune effector functions, but also has the ability to modulate host-signalling cascades involved in the development of these responses. The 19 kDa antigen (Rv3763), a lipoprotein ofM. tuberculosis, elicits high levels of interleukin (IL)-12 from macrophages in addition to its powerful immunomodulatory properties, leading to suppression of antigen-presentation signalling cascades. The present study was aimed at analysing the effect of overexpression of this antigen on the immunostimulatory properties ofM. bovisBacille Calmette–Guérin (BCG). We have constructed a recombinant BCG strain (rBCG19N) producing higher levels of the 19 kDa antigen in both the cytoplasmic (approximately eightfold) and extracellular (approximately fivefold) fractions as compared to the wildtype BCG. Immunization of mice with rBCG19N elicited high levels of interferon-gamma (IFN-γ) and relatively low levels of IL-10 against the purified 19 kDa antigen. However, in response to total BCG sonicate, mice immunized with rBCG19N produced significantly high levels of IL-10 with relatively very low levels of IFN-γ. This polarization of the host immune responses towards T-helper 2 subtype resulted in complete abrogation of the protective efficacy of BCG, when rBCG19N was used as a live vaccine againstM. tuberculosischallenge in guinea pigs. [ABSTRACT FROM AUTHOR]

The current study was planned to explore the therapeutic potency of M2000 (β-D-mannuronic acid), a novel designed non-steroidal anti-inflammatory drug (NSAID) in adjuvant-induced arthritis model. Arthritis was induced in Lewis rats by a single intradermal injection (0.1 ml) of heat-killedMycobacterium tuberculosis(0.3 mg) in Freund's incomplete adjuvant into the right footpad. Fourteen days after injection of adjuvant, the contralateral left footpad volume was measured. The animals with paw volumes 0.37 ml greater than normal paws were then randomized into treatment groups. Orally and intraperitoneally administrations of test drugs (M2000, 40/mg/kg/day and indomethacin, 2/mg/kg/day) were started on day 15 post-adjuvant injection and continued until final assessment on day 25. The left hind limb was removed for histological evaluation. The WEHI-164 cell line was used for assaying tolerability and matrix metalloproteinase type 2 (MMP-2) activity. MMP-2 activity was assessed using zymography. Pharmacotoxicology study was carried out on animal models based on the evaluation of serum and urine determinants, histology of kidney, gastrointestinal tolerability and body temperature. Results showed that the orally administration as well as intraperitoneally injection of M2000 to arthritic rats induced a significant reduction in paw oedema. Histopathological assessment showed a reduced inflammatory cells infiltrate in joints of treated rats, as well as the number of osteoclasts present in the subchondral bone, tissue oedema and bone erosion in the paws were markedly reduced following M2000 therapy. Cytotoxicity analysis of M2000 showed a much higher tolerability compared with other tested drugs (diclofenac, piroxicam and dexamethasone). The inhibitory effect of M2000 in MMP-2 activity was significantly greater than that of dexamethasone and of piroxicam at a concentration of 200µg/ml. Moreover, the toxicological study revealed that M2000 had no influence on serum (blood urea nitrogen, creatinine, triglyceride and cholesterol) and urine (urea and urinary protein excretion) determinants, glomerular histology and body temperature in normothermic rats and had no ulcerogenic effects on rats' stomach. Our data show that M2000, as a novel NSAID, could be strongly suggested as the safest anti-inflammatory drug for long-term administration. [ABSTRACT FROM AUTHOR]

Previous studies have showed that immunization with peptides from Ro 60 results in Sjögren's syndrome (SS)-like condition in BALB/ cmice. We hypothesized that oral feeding with Ro 60 peptide or Ro 60 would prevent the disease. Four groups (each consisting of 10) of BALB/ cmice were used. Group I–III were immunized with Ro 274 peptide. Group IV mice were administered adjuvant only. Group II mice were fed orally with Ro 274 peptide and Group III with Ro 60 for 5 days before immunization. There was a significant reduction in the binding of sera from both Group II and Group III mice to most of the Ro multiple antigenic peptides bound by Group I mice. In Group III mice, salivary flow was maintained above that of the Group I mice (average: 117.5 versus 58.6 µl; t = 2.7;P = 0.02). Salivary infiltrates were drastically decreased in the Ro peptide or Ro 60-fed groups, compared to non-tolerized group. Two of eight mice in Group II and 3/6 mice in Group III had no infiltrates, whereas all eight mice studied in Group I had a significant number of infiltrates. Thus, epitope spreading was prevented, lymphocytic infiltration was blocked and saliva flow was restored by means of oral feeding of either Ro 274 or Ro 60 in this animal model of SS. [ABSTRACT FROM AUTHOR]

This investigation was planned to assess the therapeutic efficacy of glucuronoxylomannan (GXM) in collagen-induced arthritis (CIA). GXM was isolated from culture filtrate of Cryptococcus neoformans var. gattii, serotype C. CIA was induced by the immunization of Dark Agouti rats with bovine type II collagen in incomplete Freund's adjuvant. GXM solution at two doses, 25 and 50 mg/kg, was administered intraperitoneally. Onset of i.p. injections of GXM to prevention and treatment groups was days 0 and 10 postimmunization, respectively. The WEHI-164 cell line was used for assaying tolerability, matrix metalloproteinase type 2 (MMP-2) activity and apoptosis. MMP-2 activity was assessed using zymography. For assessment of apoptosis, the terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labelling method was used. The results of this experiment showed that the treatment of CIA with GXM at a dose of 50 mg/kg could suppress disease development both prophylactically and therapeutically. This beneficial effect of GXM was associated with a significant decrease in the anti-CII antibody response compared with untreated rats. Moreover, GXM therapy could diminish MMP-2 activity, but it had no notable effect on apoptosis. GXM also showed a high tolerability compared with certain steroidal and non-steroidal anti-inflammatory drugs. We conclude that GXM suppresses the development of disease in CIA and it could be recommended as a new immunosuppressive and anti-inflammatory agent for further investigations. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSC) are immunomodulatory and inhibit lymphocyte proliferation. We studied surface expression of lymphocyte activation markers and secreted cytokines, when lymphocytes were activated in the presence of MSC. MSC suppressed the proliferation of phytohaemagglutinin (PHA)-stimulated CD3+, CD4+ and CD8+ lymphocytes. MSC significantly reduced the expression of activation markers CD25, CD38 and CD69 on PHA-stimulated lymphocytes. Mixed lymphocyte culture (MLC) supernatants containing MSC suppressed proliferation of MLC and PHA-stimulated lymphocytes dose-dependently. MSC secrete osteoprotegerin (OPG), but not hepatocyte growth factor (HGF) or transforming growth factor-β (TGF-β). Stromal-cell-derived factor-1 (SDF-1) is not expressed on the cell surface. A recent report suggested that T-cell suppression by MSC is mediated by HGF and TGF-β. MSC suppression was not restored by the addition of neutralizing antibodies against SDF-1, OPG, HGF or TGF-β, alone or in combination. Addition of guanosine to PHA-stimulated lymphocyte cultures containing MSC did not affect lymphocyte proliferation. The immunosuppressive effects of cyclosporine and MSC did not interfere, when present in the cultures of PHA-activated lymphocytes. In summary, human MSC suppress proliferation of both CD4+ and CD8+ lymphocyte and decrease the expression of activation markers. [ABSTRACT FROM AUTHOR]

Abstract Poor immunogenicity and major histocompatibility complex (MHC) restriction of immune responses to certain recombinant proteins or synthetic peptides impose problems in developing effective vaccines. EB200 is one of the vaccine candidate antigens from Plasmodium falciparum , which induces MHC-restricted immune responses in mice of different haplotypes. A way of overcoming this problem is to conjugate the antigen to an immunogenic protein carrier and to use optimal adjuvant substances. We have investigated the carrier effect of glutathione-S-transferase (GST) in CBA and C57BL/6 mice which are high and low responder to EB200, respectively. Our results reveal that the MHC restriction in C57BL/6 mice was broken by the use of GST as a carrier. Studies on the B-cell repertoires in both strains of mice immunized with GST-EB200 by preparing hybridoma cell lines indicate that the B-cell repertoires were similar in both CBA and C57BL/6 mice. However, the antibody affinity and the magnitude of the response were still lower in the low-responder C57BL/6 mice compared with that in CBA even when cholera toxin (CT) was used as adjuvant. To improve the response, the efficacy of various adjuvant substances like alum and Hsp 70 from Trypanosoma cruzi and the combination of various adjuvants was analysed. CT and Hsp 70 together act synergistically and markedly improve the immunogenicity of EB200 by increasing antibody affinity and the magnitude of the responses in C57BL/6 mice, which may be explained by the complementary effect of adjuvants. These results are of importance in the design of efficient vaccines. [ABSTRACT FROM AUTHOR]

When conjugated to various proteins, the nontoxic B-chain of cholera toxin (CTB) significantly increases the ability of these proteins to induce immunological tolerance after oral administration. Here, we investigated if a nonconjugated form of CTB enhances the induction of immune tolerance after oral insulin administration. Induction of immunological tolerance was studied after oral administration of insulin preparations in three mouse models; an insulin/ovalbumin coimmunization model, a model of virus-induced diabetes in transgenic RIP-LCMV-NP mice and in nonobese diabetic (NOD) mice serving as a model of spontaneous diabetes. In the immunization model, we demonstrate that mixing with CTB increases the tolerogenic potential of insulin, approximately 10 fold. Titration of the CTB concentration in this system revealed that an insulin : CTB ratio of 100 : 1 was optimal for the induction of bystander suppression. Further studies revealed that this insulin : CTB ratio also was optimal for the prevention of diabetes in a virus-induced, transgenic diabetes model. In addition, the administration of this optimal insulin-CTB preparation significantly prevented the onset of diabetes in old NOD mice with established islet infiltration. The data presented here demonstrate that CTB, even in its unconjugated form, functions as a mucosal adjuvant, increasing the specific tolerogenic effect of oral insulin. [ABSTRACT FROM AUTHOR]

Abstract An immunization protocol that induces antibodies (Abs) directed to cryptic epitopes of a protein antigen (Ag) reduces the efficacy of vaccines that ideally should induce Abs against native epitopes. We have shown earlier that viral infections concomitant with immunization against a protein tend to shift the Ab specificity toward cryptic epitopes and tend to induce the production of autoantibodies (autoAbs). Here, we show the effects of three adjuvants on the Ab specificity in the absence or presence of a viral infection (lactate dehydrogenase-elevating virus or LDV), with human growth hormone (hGH) being, as before, the protein Ag. Pathogen-free CBA/Ht and BALB/c mice were immunized with hGH in the presence of complete Freund's adjuvant (CFA), monophosphoryl lipid A (MPL) or alum, with the animals being either infected with LDV or not infected with LDV. Conventional and competition enzyme-linked immunosorbent assays (ELISAs) indicated that in noninfected mice, CFA induced higher titres of anti-hGH Ab than did MPL or alum, with the Ab being almost totally directed to cryptic hGH epitopes. Strikingly, CFA plus LDV infection in CBA/Ht mice shifted the specificity of the anti-hGH Ab toward native epitopes, whereas the virus decreased the Ab titre when MPL or alum was used. Our Western blot results showed that 70% of mice immunized with hGH in the presence of any adjuvant produced autoAbs against a variety of tissue Ags. The amount of autoAb and the concentration of Ab to hGH cryptic epitopes did correlate, suggesting a relationship between both kinds of Ab. Significant differences were observed in the various effects of adjuvants and the viral infection between the two mouse strains used in this work. [ABSTRACT FROM AUTHOR]

Abstract Streptococcus pneumoniae is a major respiratory pathogen in infants, children and the elderly. Available parenteral anti-pneumococcal vaccines based on type-specific capsular polysaccharides (CPSs) are useful in adults but do not elicit protective immunity in infants and young children. To enhance their immunogenicity, pneumococcal CPSs conjugated to proteins are being developed. Mucosal vaccines may induce mucosal and systemic immune responses, but their development has been hampered by the lack of effective, inexpensive innocuous mucosal adjuvants or immunogenic vaccine carriers. We have demonstrated that the recombinant Cry1Ac protoxin from Bacillus thuringiensis is highly immunogenic and has mucosal and systemic adjuvant effects on proteins coadministered in mice. In this work, we evaluated Cry1Ac as a carrier and adjuvant of S. pneumoniae CPS for the induction of mucosal and systemic antibody responses after intranasal and intraperitoneal immunization in mice. Our results demonstrate that intranasal application of pneumococcal polysaccharides either coadministered or conjugated with Cry1Ac induces higher systemic and mucosal specific antibody responses than those elicited by pneumococcal polysaccharides alone. Adjuvant effects of Cry1Ac on polysaccharides may be appropriate for vaccine design. [ABSTRACT FROM AUTHOR]

Increasing evidence has placed hormones and neuropeptides among potent immunomodulators, in both health and disease. Herein, we focus on the effects of growth hormone (GH) upon the thymus. Exogenous GH enhances thymic microenvironmental cell-derived secretory products such as cytokines and thymic hormones. Moreover, GH increases thymic epithelial cell (TEC) proliferation in vitro, and exhibits a synergistic effect with anti-CD3 in stimulating thymocyte proliferation, which is in keeping with the data showing that transgenic mice overexpressing GH or GH-releasing hormone exhibit overgrowth of the thymus. GH also influences thymocyte traffic: it increases human T-cell progenitor engraftment into the thymus; augments TEC/thymocyte adhesion and the traffic of thymocytes in the lymphoepithelial complexes, the thymic nurse cells; modulates in vivo the homing of recent thymic emigrants, enhancing the numbers of fluroscein isothiocyanate (FITC)[sup +] cells in the lymph nodes and diminishing them in the spleen. In keeping with the effects of GH upon thymic cells is the detection of GH receptors in both TEC and thymocytes. Additionally, data indicate that insulin-like growth factor (IGF)-I is involved in several effects of GH in the thymus, including the modulation of thymulin secretion, TEC proliferation as well as thymocyte/TEC adhesion. This is in keeping with the demonstration of IGF-1 production and expression of IGF-1 by TEC and thymocytes. Also, it should be envisioned as an intrathymic circuitry, involving not only IGF-1, but also GH itself, as intrathymic GH expression is seen both in TEC and in thymocytes, and that thymocyte-derived GH could enhance thymocyte proliferation. Finally, the possibility that GH improve thymic functions, including thymocyte proliferation and migration, places this molecule as a potential therapeutic adjuvant in immunodeficiency conditions associated with thymocyte decrease and loss of peripheral T cells. [ABSTRACT FROM AUTHOR]

Cholera toxin (CT) and heat‐labile toxin (LT) of Escherichia coli act as adjuvants for the enhancement of mucosal and serum antibody (Ab) responses to mucosally co‐administered protein antigen (Ag). Both LT and CT induce B7‐2 expression on antigen‐presenting cells (APCs) for subsequent co‐stimulatory signalling to CD4+ T cells. CT directly affects CD4+ T cells activated via the TCR–CD3 complex with selective inhibition of Th1 responses whereas LT maintains Th1 cytokine responses with inhibition of interleukin (IL)‐4 production. Interestingly, while CT failed to induce mucosal adjuvant activity in the absence of IL‐4, LT did so. Nontoxic mutant (m)CTs (S61F and E112K) retain adjuvant properties by inducing CD4+ Th2 cells, which provided effective help for the Ag‐specific mucosal immunoglobulin (Ig)A, as well as serum IgG1, IgE and IgA Ab responses. The mCT E112K has been shown to exhibit two distinct mechanisms for its adjuvanticity. Firstly, mCT enhanced the B7‐2 expression of APCs. Secondly, this nontoxic CT derivative directly affected CD4+ T cells and selectively inhibited Th1 cytokine responses. Thus, several lines of evidence indicate that enzyme activity can be separated from adjuvant properties of CT and this offers promise for the development of safe delivery of vaccines for mucosal IgA responses. [ABSTRACT FROM AUTHOR]

The lack of defined triggers for human inflammatory joint diseases warrants efforts to identify candidate molecules. For this task, it may be an important lead that nonspecific activation of the immune system can precipitate arthritis in rats. Consequently, arthritis-prone rat strains were used to search for disease-triggering factors among molecules which initially induce innate defence reactions rather than specific immune responses. A variety of immunological adjuvants were investigated by intradermal injection into DA and LEW.1AV1 rats and monitoring of clinical signs for 30 days. Several arthritogenic cell-wall structures from yeast and bacteria were identified, such as β-glucan, lipopolysaccharide and trehalosedimycolate. The test procedures also revealed arthritogens of chemical origin, such as dioctadecyldiammoniumbromide (DDA = C38H80NBr) and heptadecane (C17H36). Furthermore, it allowed the precise definition of arthritogenic determinants of lipids, since C16H34 induced arthritis, whereas the closely related linear hydrocarbons C16H32, C16H33Br and C15H32 did not. The observed pathogenicity of organic lipids raised the question of whether endogenous lipids can also precipitate arthritis. Indeed, this was true for the cholesterol precursor squalene (C30H50). In conclusion, this article describes the rational use of arthritis-prone rat strains to identify arthritogenic factors of both foreign and self origin. Although structurally unrelated, the pathogenic molecules defined here share the feature of being nonspecific triggers of the immune system. This consolidates a general principle for the induction of adjuvant arthritis which may provide clues to the aetiology of human arthritides, including rheumatoid arthritis. [ABSTRACT FROM AUTHOR]

The kinetics of sensitization and elicitation of delayed-type hypersensitivity in mice to both infectious and non-infectious preparations of influenza virus was found to be similar to that of some protein antigens and to other viruses. Sensitization was achieved without added adjuvant. Maximum DTH was elicited in the footpad 6 days after sensitization. Adoptive transfer experiments showed that the effector cells were in the Ig-negative fraction of the spleen and were sensitive to anti-θ and complement. A comparison was made of conditions for the generation of DTH activity with cytotoxic T cells. The route of inoculation was important. With a high dose (103 HAU) of virus, subcutaneous inoculation was the most efficient and intravenous injection the least efficient for sensitizing for DTH, whereas the reverse was found for cytotoxic T-cell generation. Second, treatment of mice with cyclophosphamide (Cy) had differential effects. Preinjection of a large dose (200 mg/kg) into mice 2 days before sensitization with virus resulted in an increase in the DTH response and a 90% reduction in cytotoxic T-cell activity in the spleens of the treated mice. The Cy-injected mice had reduced (70%) anti-haemagglutinin levels compared with the controls. This may be the explanation for the enhanced DTH response, since transfer of specific antibody to sensitized mice before injection of the eliciting virus substantially reduced the DTH response. Pretreatment with Cy did not affect the generation of DTH effector cells, since spleen cells from these and control mice had similar levels of activity. [ABSTRACT FROM AUTHOR]

An attempt has been made to characterize the cell type which releases blastogenic factor(s) (BF) on purified protein derivative (PPD) stimulation in complete Freund's adjuvant (CFA)-sensitized guinea-pig system and, further, to examine whether macrophages (Mϕ) are required for antigen activation of T or B lymphocytes to produce this lymphocyte. Both T and B lymphocyte populations from guinea-pigs 2 3 weeks after CFA sensitization (early-stage T and B cells) failed to produce significant amounts of BF in response to PPD, whereas both the populations from 10 to 14 weeks after sensitization (late-stage T and B cells) acquired the ability to produce BF by themselves. It is noteworthy that readded autologous M9 not only functioned well to augment BF production by the late-stage T and B cells but also completely made up for the inability of the early-stage T and B cells to produce BF. From these data it is reasonable to conclude that in the guinea-pig sensitized T and B cells can both release BF on exposure to PPD and that Mϕ either reconstitute or augment the BF synthetic response of T und B cells. [ABSTRACT FROM AUTHOR]

Antigen-pulsed macrophages (Mph) could sensitive syngeneic mice for delayed-type hypersensitivity (DTH) and also elicit sensitivity from mice sensitized to antigen in adjuvant provided these were syngeneic or semi-allogencic to the strain providing the Mph. Sensitivity could not be elicited with antigen-pulsed allogeneic Mph. Antigen-pulsed Mph from low-responder (LR) strains could not sensitive LR mice nor F1 hybrids between responder (R) and LR strains. Normal F1 mice could be sensitized to respond to antigen presented on Mph of either parental type (i.e. P1 or P1): if, however, they were sensitized to antigen on P1 Mph. DTH transfer was restricted to naive P1 mice, not to P2 (restriction imposed by priming). F1, T cells derived from stem cells differentiating in a P1 thymus graft could be sensitized but could transfer sensitivity only to naive P1 mice, not to P2 (restriction imposed in thymus). When an antigen under Ir gene control was used. LR derived T cells differentiating in an (R × LR)F1, thymus could he sensitized but only if antigen was presented on (R × LR)F1 Mph not on LR Mph. Totally allogeneic chimaeras could be sensitized but only if given antigen in association with the appropriate Mph. These findings suggest that restriction of T cell activities can be imposed as a result of priming in some cases and as a result of differentiation within the thymus in others. LR strains appear to have a lesion at the level of antigen presentation by Mph; whether they also have a defect at the level of generation of T cell repertoire cannot be determined from the present investigations. [ABSTRACT FROM AUTHOR]

In vitro exposure of mouse thymocytes to complexes of polyadenylic:polyuridylic acid (poly A:U) effected, within 6 h, the release of soluble factor(s) capable of nonspecifically enhancing IgM and IgG plaque-forming cells (PFCs) in in vitro primary and secondary spleen cell responses to burro erythrocytes. Poly A:U stimulation was, most likely, polyclonal, since production of soluble factor(s) occurred in the absence of antigen and in serum-free culture media. Poly A:U-induced soluble factor(s) were not capable of substituting for T cells but were dependent on T cells for the expression of PFC enhancement. These data support the hypothesis that the mechanism of poly A:U's adjuvant action is polyclonal stimulation of T cells, causing early induction and release of nonspecific, soluble PFC-enhancing factor(s). [ABSTRACT FROM AUTHOR]

Delayed-type hypersensitivity was induced in mice by injecting keyhole limpet haemocyanin or human serum albumin in Freund's complete adjuvant. Four techniques for assessing specific skin reactions in these immunized animals were compared: increase in thickness of the footpad; increase in thickness of the ear; arrival of 51Cr-labelled syngeneic lymph node cells at the challenge site in the ear; and accumulation of [125I]IUdR at the challenge site in the ear. The most sensitive and reliable test for detecting strong and weak reactions proved to be measurement of antigen-induced thickening in the ear. [ABSTRACT FROM AUTHOR]

Lysis of DNP-coated chicken erythrocytes by human blood lymphocytes (K cells) was induced by means of rabbit anti-DNP antibodies, Antisera were prepared by injecting the animals with DNP-conjugated proteins emulsified in Freund's complete adjuvant. An ammonium sulphate precipitation technique was used for assay of antibody concentration and affinity, Sephadex G-200 chromatography indicated that 90% of the DNP antibodies were 7S in the bleedings on days 10–16, whereas 99.8% were 7S in later bleedings, 7S antibodies induced K-cell lysis at high dilutions, whereas 19S antibodies were essentially negative. Antibody fractions obtained by DEAE- or CM-cellulose chromatography were used to establish possible heterogeneities in the capacity of 7S antibodies to induce either K-cell- or complement-mediated target cell lysis. No such heterogeneities were found. Fifteen IgG preparations containing antibodies of different affinities were compared with regard to their capacity to induce K-cell-mediated lysis. A statistically significant correlation was found between antibody affinity and efficiency in K-cell-mediated lysis. In a similar study of complement-mediated lysis the correlation was not significant at the 5% level but was significant at the 10% level. [ABSTRACT FROM AUTHOR]

We have studied the effects of lipopolysaccharide (LPS) on the primary in vivo immune response to the hapten (4-hydroxy-3,5-dinitrophenol)acetyl (NNP), with special reference to the avidity and affinity of the early appearing 19S and 7S antibodies. Comparisons were made of the immune response to NNP in groups of mice given either antigen alone, LPS alone, or antigen plus LPS. The avidity of antibodies induced by LPS plus antigen was similar to that found after injection of antigen alone, in spite of the fact that the antibodies were more numerous. However, when comparing the avidity of antibodies produced in animals given only LPS with those given LPS plus antigen, the litter group was often found to have fewer low-avidity 19S-antibody-producing cells. The affinity of 7S antibodies was also similar in the two groups given antigen or antigen plus LPS. Kinetic studies of the effect of LPS on the primary immune response to NNP showed that synergy was observed only before or after the peak response in groups given antigen alone. It is concluded that LPS under synergy conditions acts preferentially on specific antigen-sensitive cells, which are distinct from those that are activated to polyclonal antibody synthesis by LPS alone Possible mechanisms for the adjuvant effect of LPS are discussed. [ABSTRACT FROM AUTHOR]

We found that chickens responded to an injection of 1 mg of alum-precipitated conjugates of (4-hydroxy-3-iodo-5-nitrophenyl)acetyl and bovine serum albumin (NIP-BSA) or human gammaglobulin (NIP-HGG) with an anti-NIP response. This response was enhanced to fivefold titers if the birds were given a small dose (2 or 0.2 μg) of the carrier protein in complete Freund's adjuvant a week before injection. If the dose of the carrier was large (200-2,000 μg), it decreased the subsequent anti-NIP response to the conjugate. The effect of the preimmunization correlated with the formation of anti-carrier antibodies: a good anti-carrier response was connected with inhibition and a poor anti-carrier response with enhancement of the anti-NIP response. Large preimmunization doses of the carrier caused enhanced anti-hapten responses if the carrier was methylated or dodecanoylated; in this case the anti-carrier humoral responses were weak. Large doses of the native carrier increased the subsequent anti-hapten response if spleen cells of the preimmunized donors were injected into cyclophosphamide-treated donors, who were then immunized with the hapten conjugate. The results confirm earlier studies indicating that collaboration of carrier-specific cells and haptenspecific cells is required in the chicken for an optimal anti-hapten response. They further indicate that carrier-primed cells do not reside in the thymus and that, also in birds, immunization by methylated or dodecanoylated protein causes good priming for helper function but bad priming for the antibody formation against the protein. [ABSTRACT FROM AUTHOR]

Examines the central concepts of specific immunity to tumors. Basic assumptions in tumor biology; Reasons behind the irrelevance of in vitro studies of T cell or killer cell cytotoxicity to the in vivo reality; Description of what happens at the cellular and tissue levels during immunomodulator-caused rejections.

Mannuronan (poly-β-(1→4)-D-mannuronate or poly-M), produced by Pseudomonas aeruginosa as a mucoid exopolysaccharide, has previously been shown to exhibit immunostimulating activity. The authors investigated the in vivo and in vitro effects of mannuronan on murine haematopoiesis. In vivo, prophylactic (-24 h, intraperitoneal) administration of mannuronan enhanced survival of lethally Irradiated mice from zero day 40 survivors (NaCl) to 20. 80 and 70% survival at 0.5, 1 and 2 mg/kg bw mannuronan, respectively. In vitro, primary stromal cultures stimulated with mannuronan produced high levels of interleukin(IL)-1, IL-6 and colony stimulating activity. Mannuronan alone did not have any colony stimulating activity on GM-CFC, BFU-E. Mix-CFC or HPP-CFC progenitors in clonogenic assays, but acted synergistically with suboptimal amounts of growth factors on GM-CFC, Mix-CFC and HPP-CFC colony formation. Limiting dilution analysis showed that 1 of 423 bone marrow cells formed colonies in response to suboptimal GM-CSF plus mannuronan compared to 1 of 592 for suboptimal GM-CSF alone. The primitive Lin-Sca-1+ haematopoietic progenitors showed increased day 10 colony size in the presence of mannuronan in single cell assays. These stimulating effects of mannuronan on haematopoiesis may prove to have clinical importance. [ABSTRACT FROM AUTHOR]

It is demonstrated that the biological effects of the immunomodulator β1-3D polyglucose, when covalently linked to polymethacrylate or biodegradable albumin microbeads, are strongly potentiated. The potentiation is recorded as an increased protection effect of the conjugates in Escherichia coli sepsis in mice, and as increased IL-1 production by murine macrophages in vitro. [ABSTRACT FROM AUTHOR]