Influence of immunopotentiators on the antiporin immunoglobulin G subclass: Distribution and protective immunity against murine salmonellosis

To improve the immune potential of porin (a pore-forming protein of Salmone lla sp.), different immunopotentiators such as Freund's complete adjuvant ( FCA), lipopolysaccharide (LPS) and polyoxydonium (PO) were evaluated by stu dying the nature of the protective immune response induced against murine S almonellosis. The nontoxic, synthetic heteropolymer polyoxydonium was as go od as LPS at inducing antiporin immunoglobulin G (IgG) antibodies and prote ctive immunity. Analysis of the antiporin IgG subclass pattern revealed a p referential increase in a particular subclass based on the immunopotentiato r used. Porin, alone or emulsified in FCA, elicited predominantly antiporin IgG(1) antibodies, whereas LPS preferentially evoked antiporin IgG(2a). Ig G(2b) and IgG(3) antibodies. Polyoxydonium induced a clear shift towards an tiporin TgG(2b) antibodies. The significance of these antiporin IgG subclas s antibodies in protection against murine Salmonellosis was studied by pass ive immunization and by analysing the infected mouse sera.