Immunogenic characterization of vaccines based on ce:italic>Haemophilus parasuis/ce:italic> Nagasaki strain, OmpP2, OmpP5 and OmpD15, in colostrum-deprived pigs experimentally challenged with the same strain

摘要

Three recombinant outer membrane proteins (rOmps) from theHaemophilus parasuisNagasaki strain (serovar 5 reference strain), rOmpP2, rOmpP5 and rOmpD15, which have previously shown protection againstH. parasuisinfection in mice, were cloned, expressed and evaluated as vaccine antigens in colostrum-deprived pigs. When these animals were immunized with these rOmps and were later challenged intratracheally with 108CFUs of the Nagasaki strain, no protection was seen in terms of survival, clinical signs, pathological results and recovery ofH. parasuis. We hypothesized that a possible explanation for this lack of protection could be the low number of epitopes accessible to the immune system as a consequence of their poor exposure on the bacterial surface so that the immune response would not be able to protect against experimental infection byH. parasuiswhen a fully susceptible animal model, such as pigs, was used.