IN-VITRO EVALUATION OF THE ROLE OF HUMORAL IMMUNITY AGAINST BARTONELLA-HENSELAE

The contribution of humoral immunity against Bartonella henselae was e valuated by examining the in vitro bactericidal activity of sera and t he ability of these microorganisms to activate complement and stimulat e phagocytosis and an oxidative burst in polymorphonuclear leukocytes. The organism was killed by complement-mediated cytolysis. Complement activation preferentially proceeded by the alternative pathway. The pr esence of specific antibodies did not increase the serum bactericidal activity or complement activation. However, phagocytosis and the subse quent production of oxygen radicals, evaluated by flow cytometry, were significantly enhanced in the presence of bacteria previously opsoniz ed with immune sera.