MURINE IGG SUBCLASS ANTIBODIES TO ANTIGENS INCORPORATED IN LIPOSOMES CONTAINING LIPID-A

The IgG subclass responses to antigens incorporated in liposomes conta ining lipid A were investigated using a synthetic malarial antigen (SP f66) and cholera toxin (CT). The antigen-specific IgG subclass respons e was determined in BALB/c mice immunized with either: (a) SPf66 encap sulated in liposomes containing lipid A, (b) CVT bound to the surface of liposomes containing lipid A, or (c) both encapsulated SPf65 and su rface-bound CT in the same liposomes. In each case the antibodies to S Pf66, CT and lipid A demonstrated an IgG2a predominance. Liposomes con taining lipid A not only increased the magnitude of the antibody respo nse to liposomal antigens but elicited predominantly IgG2a subclass an tibodies as well.