EFFECT OF PASTEURELLA-MULTOCIDA VACCINATION ON BUFFALO POLYMORPHONUCLEAR HYDROGEN-PEROXIDE AND NITRIC-OXIDE PRODUCTION

An attempt was made to investigate the effect of Pasteurella multocida on certain microbicidal reactive oxygen and nitrogen intermediates re leased by the polymorphonuclear cells (PMNs) from the vaccinated anima ls. The PMNs from the peripheral blood of both control and experimenta l buffaloes vaccinated against haemorrhagic septicaemia were isolated. PMNs from control animals upon activation with P. multocida lipopolys accharide (LPS) and live P. multocida cells generated higher levels of hydrogen peroxide (H2O2) and nitric oxide (NO-) than the non-activate d cells (P < 0.01). In the presence of P. multocida LPS, PMNs from ani mals vaccinated against haemorrhagic septicaemia generated significant ly higher H2O2 (P < 0.05) and NO- (P < 0.01) than the PMNs from contro l animals. L-Arginine when added to the activation medium enhanced the production of NO- in a dose-dependent manner. This indicated the role of arginine in NO- production, The study suggested that buffalo PMNs possessed a potent oxidant defence system even in the presence of P. m ultocida, an antiphagocytic bacterium.