Lymphocyte transformation to membrane-conjugated, liposome-conjugated, or unconjugated pentadecylcatechol in the guinea pig

This study examined the in vitro immunogenicity of haptenated liposomes and compared them with haptenated biological membranes and unconjugated hapten. Peripheral-blood lymphocytes were obtained from guinea pigs topically sensitized with pentadecylcatechol (PDC) and immunologically naive guinea pigs. Lymphocyte transformations were studied by [3H]thymidine uptake. PDC failed to stimulate the lymphocytes from the immunologically naive group. There was significant blastogenesis in the cells of the sensitized group, but the degree of stimulation was dependent upon the manner in which the antigen was presented to them. Unconjugated hapten caused a low-level, dose-dependent mitogenesis in the sensitized T cells, and hapten-conjugated liposomes enhanced this response (P less than 0.05). By far the most effective immunogen was a haptenated biologic membrane. In all cases, the mitogenic response was macrophage dependent. It is possible that the haptenated biologic membranes were more effective than synthetic membranes (liposomes) because of the presence of membrane proteins that can conjugate with hapten and from a more effective immunogen.