Galectin-8 activates dendritic cells and stimulates antigen-specific immune response elicitation.

Galectin-8 (Gal-8) is a mammalian ß-galactoside-binding lectin, endowed with proinflammatory properties. Given its capacity to enhance antigen-specific immune responses in vivo, we investigated whether Gal-8 was also able to promote APC activation to sustain T cell activation after priming. Both endogenous [dendritic cells (DCs)] and bone marrow-derived DCs (BMDCs) treated with exogenous Gal-8 exhibited a mature phenotype characterized by increased MHC class II (MHCII), CD80, and CD86 surface expression. Moreover, Gal-8-treated BMDCs (Gal-8-BMDCs) stimulated antigen-specific T cells more efficiently than immature BMDCs (iBMDCs). Proinflammatory cytokines IL-3, IL-2, IL-6, TNF, MCP-1, and MCP-5, as well as growth factor G-CSF, were augmented in Gal-8-BMDC conditioned media, with IL-6 as the most prominent. Remarkably, BMDCs from Gal-8-deficient mice (Lgals8-/- BMDC) displayed reduced CD86 and IL-6 expression and an impaired ability to promote antigen-specific CD4 T cell activation. To test if Gal-8-induced activation correlates with the elicitation of an effective immune response, soluble Gal-8 was coadministrated with antigen during immunization of BALB/cJ mice in the experimental foot-and-mouth disease virus (FMDV) model. When a single dose of Gal-8 was added to the antigen formulation, an increased specific and neutralizing humoral response was developed, sufficient to enhance animal protection upon viral challenge. IL-6 and IFN-γ, as well as lymphoproliferative responses, were also incremented in Gal-8/antigen-immunized animals only at 48 h after immunization, suggesting that Gal-8 induces the elicitation of an inflammatory response at an early stage. Taking together, these findings argue in favor of the use of Gal-8 as an immune-stimulator molecule to enhance the adaptive immune response.

Using mixed methods to investigate factors influencing reporting of livestock diseases: a case study among smallholders in Bolivia.

Livestock disease surveillance is particularly challenging in resource-scarce settings, where disease events are often unreported. Surveillance performance is determined as much by the quantifiable biological attributes of the disease, as it is by motivations and barriers perceived by livestock keepers for disease reporting. Mixed methods designs, which integrate the collection, analysis and interpretation of qualitative and quantitative data in a single study, are increasingly used across different disciplines. These designs allow for a deeper exploration of the topic under investigation, than can be achieved by either approach alone. In this study a mixed methods design was used in order to gain a greater understanding of the factors that influence reporting of livestock diseases in Bolivia. There is a need to strengthen passive surveillance in this country, among other reasons as part of an eradication programme for Foot and Mouth Disease (FMD). Findings revealed livestock keepers in the study area were extremely unlikely to report the occurrence of livestock health events to the Official Veterinary Services (OVS). Communication outside the local community occurs more often through alternative routes and this is positively correlated with disease awareness. The main barriers to disease reporting identified were a lack of institutional credibility and the conflicting priorities of the OVS and livestock keepers. As for other animal and human diseases across the developing world, passive surveillance of livestock diseases in Bolivia should be enhanced; this is urgent in view of the current FMD eradication programme. Increasing timeliness and smallholders' participation requires a detailed understanding of their likely actions and perceived barriers towards disease reporting. These insights are most likely to be developed through a holistic mixed methods approach of quantitative and qualitative analyses.

Transient gene expression in serum-free suspension-growing mammalian cells for the production of foot-and-mouth disease virus empty capsids.

Foot-and-mouth disease (FMD) is a highly contagious disease of cloven-hoofed animals. It produces severe economic losses in the livestock industry. Currently available vaccines are based on inactivated FMD virus (FMDV). The use of empty capsids as a subunit vaccine has been reported to be a promising candidate because it avoids the use of virus in the vaccine production and conserves the conformational epitopes of the virus. In this report, we explored transient gene expression (TGE) in serum-free suspension-growing mammalian cells for the production of FMDV recombinant empty capsids as a subunit vaccine. The recombinant proteins produced, assembled into empty capsids and induced protective immune response against viral challenge in mice. Furthermore, they were recognized by anti-FMDV bovine sera. By using this technology, we were able to achieve expression levels that are compatible with the development of a vaccine. Thus, TGE of mammalian cells is an easy to perform, scalable and cost-effective technology for the production of a recombinant subunit vaccine against FMDV.

Baculovirus treatment fully protects mice against a lethal challenge of FMDV.

Foot-and-mouth disease virus (FMDV) causes a highly contagious and economically devastating disease that affects cattle, swine, goat and sheep among others. FMDV is able to overcome the initial host innate immune response by inhibiting the induction of antiviral molecules at both the transcriptional and the translational levels. It has been demonstrated that FMDV A/Arg/2001 causes the death of adult C57Bl/6 mice within 72h. We evaluated the capacity of Autographa californica nuclear polyhedrosis virus (AcNPV), an insect virus with potent innate immunostimulating effects, to promote early protection against FMDV A/Arg/2001 challenge in C57Bl/6 mice. Groups of 8-9 weeks old female mice were injected intravenously with AcNPV and challenged with a lethal dose of FMDV at different times post-administration. Our results showed that pretreatment of mice with a single injection of AcNPV 3h or 3 days before FMDV challenge resulted in complete abrogation of mortality and complete or partial suppression of viremia, respectively. Furthermore, no signs of disease were observed. AcNPV could be a valuable tool to improve the design of a novel vaccine that protects as an adjuvant at early times post-vaccination.

Differences in the virulence of two strains of Foot-and-Mouth Disease Virus Serotype A with the same spatiotemporal distribution.

During the 2000-2001 epidemic of Foot-and-Mouth Disease Virus (FMDV) in Argentina, two FMDV serotype A viruses were identified among others. Since different pathogenic properties between these virus strains were noticed in cattle, we evaluated several biological properties and features of FMDV A/Arg/00 and FMDV A/Arg/01 in order to compare these viruses in terms of virulence and pathogenicity. Our results indicate that FMDV A/Arg/00 grows less efficiently than FMDV A/Arg/01, exemplified by smaller sized plaques, retarded one-step growth curves and overall low viral yields. Also, FMDV A/Arg/00 displayed the lowest specific infectivity in suckling mice requiring 50-fold more infectious particles than FMDV A/Arg/01 to generate a LD50 in suckling mice. Finally, FMDV A/Arg/00 did not cause death in adult C57Bl/6 mice even at high doses (10(7)-10(6)PFU) whereas FMDV A/Arg/01 resulted lethal in doses as low as 10(2)PFU. Overall, we were able to demonstrate that these virus strains differ from each other in terms of virulence and pathogenicity.

Pressure-inactivated FMDV: a potential vaccine.

Foot-and-mouth disease virus (FMDV) is the causative agent of the foot-and-mouth disease (FMD). Alternative FMD vaccines have been pursued due to important disadvantages of the one currently in use. High hydrostatic pressure (HP) has been observed to inactivate some viruses. Here, we investigated the effects of HP on FMDV O1 Campos-Vallée (CVa) infectivity. A treatment consisting of 2.5 kbar at -15 degrees C and 1M urea, completely abolished FMDV infectivity, maintaining the integrity of its capsid structure. Moreover, its ability to elicit neutralizing antibody production in rabbits was preserved. Taken together, our results suggest that HP could be a safe, simple, cheap and reproducible way for viral vaccine production.

Evidence of the coevolution of antigenicity and host cell tropism of foot-and-mouth disease virus in vivo.

In this work we analyze the antigenic properties and the stability in cell culture of virus mutants recovered upon challenge of peptide-vaccinated cattle with foot-and-mouth disease virus (FMDV) C3 Arg85. Previously, we showed that a significant proportion of 29 lesions analyzed (41%) contained viruses with single amino acid replacements (R141G, L144P, or L147P) within a major antigenic site located at the G-H loop of VP1, known to participate also in interactions with integrin receptors. Here we document that no replacements at this site were found in viruses from 12 lesions developed in six control animals upon challenge with FMDV C3 Arg85. Sera from unprotected, vaccinated animals exhibited poor neutralization titers against mutants recovered from them. Sequence analyses of the viruses recovered upon 10 serial passages in BHK-21 and FBK-2 cells in the presence of preimmune (nonneutralizing) sera revealed that mutants reverted to the parental sequence, suggesting an effect of the amino acid replacements in the interaction of the viruses with cells. Parallel passages in the presence of subneutralizing concentrations of immune homologous sera resulted in the maintenance of mutations R141G and L147P, while mutation L144P reverted to the C3 Arg85 sequence. Reactivity with a panel of FMDV type C-specific monoclonal antibodies indicated that mutant viruses showed altered antigenicity. These results suggest that the selective pressure exerted by host humoral immune response can play a role in both the selection and stability of antigenic FMDV variants and that such variants can manifest alterations in cell tropism.