Antigen presentation by B cells and macrophages of cytochrome c and its antigenic fragment when conjugated to the surface of liposomes

An in vitro antigen presentation system was used to study how antigens coupled to the surface of phospholipid vesicles (liposomes) are presented to antigen specific T cells. Liposome-bound pigeon cytochrome c (PCC) was 30–40-fold more potent than free PCC when peritoneal macrophages were the presenting cell. B cells presented surface-bound PCC, albeit less efficiently than unmodified PCC. Surface-bound peptide epitope was presented by both cell types, but not as efficiently as unmodified peptide. With the T cell epitope, antigen processing was not required since glutaraldehyde fixed cells could present surface-bound peptide.