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The high viral diversity of HIV-1 is a formidable hurdle for the development of an HIV-1 vaccine. Elicitation of broadly neutralizing antibodies (bNAbs) would offer a solution, but so far immunization strategies have failed to efficiently elicit bNAbs. To overcome these obstacles, it is important to understand the immune responses elicited by current HIV-1 envelope glycoprotein (Env) immunogens. To gain more insight, we characterized monoclonal antibodies (MAbs) isolated from rabbits immunized with Env SOSIP trimers based on the clade B isolate AMC008. Four rabbits that were immunized three times with AMC008 trimer developed robust autologous and sporadic lowtiter heterologous neutralizing responses. Seventeen AMC008 trimer-reactive MAbs were isolated using antigen-specific single B-cell sorting. Four of these MAbs neutralized the autologous AMC008 virus and several other clade B viruses. When visualized by electron microscopy, the complex of the neutralizing MAbs with the AMC008 trimer showed binding to the gp41 subunit with unusual approach angles, and we observed that their neutralization ability depended on their capacity to induce Env trimer dissociation. Thus, AMC008 SOSIP trimer immunization induced clade B-neutralizing MAbs with unusual approach angles with neutralizing effects that involve trimer destabilization. Optimizing these responses might provide an avenue to the induction of trimer-dissociating bNAbs. [ABSTRACT FROM AUTHOR]

Aims In a laboratory, disinfectants used to inactivate pathogens on contaminated surfaces and to prevent spread of diseases often have adverse side effects on personnel and the environment. It is, therefore, essential to find safer, fast-acting and yet effective disinfectants. The objective of this study was to evaluate an accelerated hydrogen peroxide® ( AHP®)-based disinfectant against high consequence foreign animal disease pathogens such as foot-and-mouth disease virus ( FMDV) and swine vesicular disease virus ( SVDV), as well as Senecavirus A ( SVA), which causes similar lesions as FMDV and SVDV. Methods and Results We tested varying dilutions and contact times of AHP against FMDV, SVDV and SVA by the standard US EPA and modified methods. AHP was effective against all three viruses, albeit at a higher concentration and double the manufacturer recommended contact time when testing wet films of SVDV. Conclusions AHP is an effective disinfectant against FMDV, SVDV and SVA. Significance and Impact of the Study AHP-based disinfectant can, therefore, be used in high containment laboratories working with FMDV, SVDV and related pathogens. [ABSTRACT FROM AUTHOR]

An indirect ELISA was developed to detect antibodies specific for capripoxviruses in goat, sheep and cattle sera. Heat-inactivated Nigerian sheeppox virus was used as the ELISA antigen. Sera obtained from sheep and goats that were experimentally infected with different capripoxvirus isolates were used to develop and evaluate the sensitivity of the ELISA. Virus neutralization indexes were determined for the experimental sera in OA3.Ts cells. The specificity of the ELISA was determined using 231 sera from capripoxvirus naïve sheep and goats from Canada. In addition, the ELISA was tested for cross-reactivity to anti-orf virus antibodies using orf-reactive sera and no cross-reactivity was observed. Using experimentally generated sera obtained from animals infected with virulent sheeppox or goatpox virus isolates, the diagnostic sensitivity of the ELISA was 96% with a diagnostic specificity of 95%, where the diagnostic sensitivity of the virus neutralization assay was 96% with a diagnostic specificity of 100%. Further evaluation of this ELISA, using 276 cattle serum samples that were positive by virus neutralization assays, revealed a diagnostic sensitivity of 88% with a specificity of 97%. These results indicated that the inactivated capripoxvirus ELISA can detect capripoxvirus-specific antibodies in sheep, goats and cattle that have been infected with virulent capripoxvirus isolates. Non-virulent capripoxvirus isolates, in contrast, did not elicit positive (≥1.5 Log10 neutralization index) antibody responses. [ABSTRACT FROM AUTHOR]

Lumpy skin disease along with sheep pox and goatpox are the most serious poxvirus diseases of livestock, and are caused by viruses that belong to the genus Capripoxvirus within the subfamily Chordopoxvirinae, family Poxviridae. To facilitate the study of lumpy skin disease pathogenesis, we inoculated eight 4- to 6-month-old Holstein calves intravenously with lumpy skin disease virus (LSDV) and collected samples over a period of 42 days for analysis by virus isolation, real-time PCR and light microscopy. Following inoculation, cattle developed fever and skin nodules, with the extent of infection varying between animals. Skin nodules remained visible until the end of the experiment on day post-inoculation (DPI) 42. Viremia measured by real-time PCR and virus isolation was not observed in all animals but was detectable between 6 and 15 DPI. Low levels of viral shedding were observed in oral and nasal secretions between 12 and 18 DPI. Several tissues were assessed for the presence of virus at DPI 3, 6, 9, 12, 15, 18 and 42 by virus isolation and real-time PCR. Virus was consistently detected by real-time PCR and virus isolation at high levels in skin nodules indicating LSDV has a tropism for skin. In contrast, relatively few lesions were observed systemically. Viral DNA was detected by real-time PCR in skin lesions collected on DPI 42. Cattle developing anti-capripoxvirus antibodies starting at DPI 21 was detected by serum neutralization. The disease in this study varied from mild with few secondary skin nodules to generalized infection of varying severity, and was characterized by morbidity with no mortality. [ABSTRACT FROM AUTHOR]

Nipah virus (NiV; Paramyxoviridae) caused fatal encephalitis in humans during an outbreak in Malaysia in 1998/1999 after transmission from infected pigs. Our previous study demonstrated that the respiratory, lymphatic and central nervous systems are targets for virus replication in experimentally infected pigs. To continue the studies on pathogenesis of NiV in swine, six piglets were inoculated oronasally with 2.5 × 105 PFU per animal. Four pigs developed mild clinical signs, one exudative epidermitis, and one neurologic signs due to suppurative meningoencephalitis, and was euthanized at 11 days post-inoculation (dpi). Neutralizing antibodies reached in surviving animals titers around 1280 at 16 dpi. Nasal and oro-pharyngeal shedding of the NiV was detected between 2 and 17 dpi. Virus appeared to be cleared from the tissues of the infected animals by 23 dpi, with low amount of RNA detected in submandibular and bronchial lymph nodes of three pigs, and olfactory bulb of one animal. Despite the presence of neutralizing antibodies, virus was isolated from serum at 24 dpi, and the viral RNA was still detected in serum at 29 dpi. Our results indicate slower clearance of NiV from some of the infected pigs. Bacteria were detected in the cerebrospinal fluid of five NiV inoculated animals, with isolation of Streptococcus suis and Enterococcus faecalis. Staphylococcus hyicus was isolated from the skin lesions of the animal with exudative epidermitis. Along with the observed lymphoid depletion in the lymph nodes of all NiV-infected animals, and the demonstrated ability of NiV to infect porcine peripheral blood mononuclear cells in vitro, this finding warrants further investigation into a possible NiV-induced immunosuppression of the swine host. [ABSTRACT FROM AUTHOR]