Functional cholesteryl binding agents: evaluation of viability and specificity of antibodies bound to modified phospholipid vesicles.

A cholesterol derivative was incorporated into small unilamellar phospholipid vesicles, and antibodies were bound covalently to the vesicles. More than one antibody was bound to each vesicle. The antigen binding viability and specificity were determined using a modified radioimmunoassay and an in vitro cell assay. Both of these tests showed good antibody activity and specificity. The antigen affinity of the bound antibodies was higher than for the unbound antibody due to more than one viable antibody being bound to each vesicle. The modified vesicles can be used as immunodirected drug delivery systems for both diagnosis and therapy.