Immunization procedures for anti-idiotypic antibody induction in mice and rats

Anti-idiotypic antibodies (Ab2) mimicking antigens (Ags)-defined by antibodies (Ab1) directed to tumors or pathogens have elicited Ag-specific humoral, cellular and/or protective immunity in experimental animals and in humans. In immunizations of rodents with Ab1, factors such as animal species, form of Ab1 and choice of adjuvant are crucial for the successful induction of Ab2 as candidate vaccines against tumors and pathogens. Here we survey the outcome of 362 fusion events (each event representing one animal), using nine immunization schedules in mice and seven schedules in rats and including 10 different Ab1 directed against human tumor- and immunodeficiency virus (HIV-1)-associated Ags. Ab1 IgG or F(ab')2 were administered uncoupled or coupled to keyhole limpet hemocyanin (KLH). As adjuvants, complete and incomplete Freund's adjuvant (CFA/IFA), lipid A, aluminum hydroxide, TiterMax or vaccinia virus were used. In syngeneic immunizations with murine Ab1 in mice, F(ab')2 coupled to KLH and emulsified in CFA/IFA preferentially induced Ab2 mimicking tumor or HIV-1 associated epitopes. In xenogeneic immunizations with mouse Ab1 in rats, various forms of Ab1 and adjuvants successfully induced Ab2 mimicking tumor Ags.