Mucosal immunization provides better protection than subcutaneous immunization against Pasteurella multocida (B:2) in mice preimmunized with the outer membrane proteins.

To investigate the effect of boosting immunity via mucosal route vis-a-vis parenteral route in the mouse model of haemorrhagic septicaemia, mice preimmunized with OMP of Pasteurella multocida (B:2) were immunized with 10(2) cfu of P. multocida via intranasal and subcutaneous routes. Mice were challenged through intranasal route (natural route of infection) with 10(8) cfu 14 days after immunization. Group of mice which were immunized intranasally showed significant protection (P < 0.05) of 88% as compared to 50% protection in group of mice immunized subcutaneously. In the control group of mice, 100% mortality occurred within 48 h. of challenge. The results of present study indicated that boosting of immunity via mucosal route in mice preimmunized with OMP provided better protection against P. multocida. This study may have implications for developing better vaccination strategies for the natural host.