Importantly, no clinical signs and undetectable virus shedding were observed after virulent PPRV challenge in vaccinated sheep
Importantly, no clinical signs and undetectable virus shedding were observed after virulent PPRV challenge in vaccinated sheep. contagious disease of small ruminants, mainly sheep and goats, notifiable to the World Organization for the Animal Health (OIE). The disease is endemic in Asia, the Middle East and Africa, and is spreading to other countries, as evidenced by the recent outbreak declared in December 2013 in China. It causes significant economical losses in endemic regions. Clinically PPR may vary from acute infection with severe clinical disease and death to mild, with little or no visible clinical signs. Acute infection may include severe pyrexia [41.0C41.3C] with affected animals often becoming restless, having a dull coat, dry muzzle, catarrhal inflammation of the ocular and nasal mucosa, diarrhoea, enteritis, pneumonia and loss of appetite . The mortality rate is comprised between 50C80% in the acute cases . The eradication in 2001 of the closely related Rinderpest Virus (RPV) has increased the global interest in PPRV because of its emergence and has highlighted the necessity to develop specific strategies for its surveillance and prevention through vaccination . The causal agent, Peste des petits ruminants virus (PPRV), belongs to the genus (CISA), in strict accordance with the recommendations in the Dolastatin 10 guidelines of the Code for Methods and Welfare Considerations in Behavioural Research with Animals (Directive 86/609EC; RD1201/2005) and Dolastatin 10 all efforts were made to minimize suffering. Experiments were approved by the Committee on the Ethics of Animal Experiments NOS3 (CEEA) of the Spanish (INIA) and the tests or two-way ANOVA were used to compare treatment groups. Responses to Con-A and IgG titres at different time points were compared using a Wilcoxon matched-pairs signed-rank test. Data handling analyses was performed using Prism 6.0 (GraphPad Software Inc. San Diego, CA, USA). Results Vaccination with recombinant Ad5 virus expressing the F or H protein induces PPRV specific IgG in sheep To determine whether the recombinant adenoviruses expressing Dolastatin 10 PPRV F or H Dolastatin 10 proteins elicited a specific immune response in sheep, groups of four animals were inoculated im with PBS, control adenovirus (Ad5) or Ad-PPRV-F or Ad-PPRV-H (Table 1). A booster inoculation was performed 21 days later. Sera were tested for the presence of PPRV-specific IgG by ELISA (Figure 1). Sheep inoculated with Ad5-PPRV-F or Ad5-PPRV-H developed PPRV-specific IgG as early as day 7 post-vaccination, whereas no virus-specific IgG were detectable in control sheep (PBS and Ad5). By the time of challenge on day 42, PPRV-specific IgG titres in vaccinated sheep increased by at least 2 logarithmic units (Figure Dolastatin 10 1). Open in a separate window Figure 1 Inoculations with Ad5-PPRV-F or Ad5-PPRV-H induce the production of PPRV-specific IgG in sheep.Groups (n?=?4) of sheep were inoculated intramuscularly with PBS, control adenovirus (Ad5), Ad-PPRV-F or Ad-PPRV-H at days 1 and 22 and all animals were challenged with virulent PPRV IVC 89 at day 42 (indicated by arrow). Serum samples obtained at the indicated time points were analysed for PPRV-specific IgG by ELISA using Nigeria 75/1 PPRV coated plates. Data are presented as average (+/?SEM) IgG titre for each treatment group. * p 0.01 in Wilcoxon matched-pairs signed rank test; day 7 vs day 0 in immunized sheep.** p 0.01 in Wilcoxon matched-pairs signed rank test; day 7 post-challenge vs day 42 pre-challenge. *** p 0.001 Mann-Whitney test: vaccinated (Ad5-PPRV-F and Ad5-PPRV-H) vs control (PBS and Ad5) sheep at the same time point. At day 42 post-vaccination, sheep were challenged with the virulent ICV’89 PPRV strain and further serum samples were collected at days 3, 7 and 13 post-challenge (pc). PPRV challenge on day 42 resulted in rapid and significant production of virus-specific IgG in control animals and a slight increase in IgG titers was also detected in vaccinated animals. Importantly, PPRV-specific IgG levels in challenged control sheep remained at least one logarithmic unit below their vaccinated counterpart. These data show.