The Comparison Detection of Cytokines (IL-6 and IL-12) from Spleen Cells and Serums in Balb/c Mice after Immunization with Killed P. multocida Vaccines Co-formulated with Bacterial DNAs as Adjuvant

Purpose: Pasteurella multocida has been correlated with commensal pathogens in the respiratory tract of birds and mammals. The purpose of the present study was to verify the cellular immune responses in Balb/c mice inoculated with the iron inactivated vaccine adjuvanted with bDNAby the detection of cytokines from spleen cells and serum. Methods: Mice were experimentally immunized with P. multocida killed antigens to study the splenocyte suspension and serum cytokines proliferation at different groups of post-immunization. We used P. multocida A (AbDNA), P. multocida B (BbDNA), S. typhimurium (SbDNA) bacterial DNAs and alum as adjuvants. Interleukin-6 (IL-6) and IL-12 titer were tested by ELISA. Results: Mice immunized with vaccine formulations containing bDNAs as adjuvant produced a higher level of interleukins than alum and control groups. The serum level of pro-inflammatory cytokines (IL-6 and IL-12) was significantly higher (p<0.01) in vaccinated animals compared to control groups. A peak of IL-6 (59.8 pg/ml) and IL-12 (26.4 pg/ml) was recorded in in vitro stimulated splenocytes in the IIA+SbDNA group. Conclusion: These findings designated that killed P. multocida antigens formulated with bacterial DNAs as an adjuvant are possible vaccine candidates against P. multocida infections. The effect of the bacterial DNAs on the cellular immune response can be exploited in the development of new vaccines.