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

• Published in: Research in veterinary science 2018-08, Vol.119, p.292-301
• Main Authors: Álvarez-Estrada, Álvaro, Martínez-Martínez, Sonia, Martín, César-Bernardo Gutiérrez, García-Iglesias, María-José, Pérez-Martínez, Claudia, Yubero-Delgado, Sheila, Guizzo, João Antônio, Frandoloso, Rafael, Rodríguez-Ferri, Elías-Fernando
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Bacterial; Antigens; Cloning; Colostrum; Deoxyribonucleic acid; Design; DNA; Epitopes; Experimental infection; Female; Glässer's disease; Haemophilus; Haemophilus Infections - immunology; Haemophilus Infections - prevention & control; Haemophilus Infections - veterinary; Haemophilus parasuis; Haemophilus parasuis - immunology; Haemophilus Vaccines - immunology; Hogs; Immune response; Immune system; Immunization; Immunogenicity; Infections; Membrane proteins; Mice; OmpD15; OmpP2; OmpP5; Outer membrane proteins; Pregnancy; Proteins; Swine; Swine Diseases - immunology; Swine Diseases - prevention & control; Vaccines; Veterinary medicine
• ISSN: 0034-5288; 1532-2661
• DOI: 10.1016/j.rvsc.2018.07.009

Three recombinant outer membrane proteins (rOmps) from the Haemophilus parasuis Nagasaki strain (serovar 5 reference strain), rOmpP2, rOmpP5 and rOmpD15, which have previously shown protection against H. parasuis infection 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 108 CFUs of the Nagasaki strain, no protection was seen in terms of survival, clinical signs, pathological results and recovery of H. 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 by H. parasuis when a fully susceptible animal model, such as pigs, was used. •We cloned, expressed & purified OmpP2, P5 and D15 from H. parasuis Nagasaki strain•These recombinant proteins were recognized by pig antibodies to H. parasuis•They elicit a rabbit humoral response recognized by whole-cell H. parasuis•These proteins showed no protection in pigs despite their humoral response