Vesicle interactions with antibody and peptide hormone: role of vesicle composition.

Artificial lipid vesicles (artificial membranes) were shown to bind human 125I-antithyroglobulin (anti-Tg) and human 125I-thyrotropin. Vesicles made with gangliosides bound more antibody and hormone than vesicles lacking them. These gangliosides contained a variety of carbohydrates including glucose, galactose, N-acetyl-galactosamine, and sialic acid. The in vivo stability of antibody-vesicle complexes was a function of vesicle composition: vesicles were most stable when formed from phosphatidylcholine, cholesterol, and gangliosides. Anti-Tg-vesicle complexes bind to thyroglobulin, indicating that at least some of the antibody associated with the vesicle still retains ability to bind to its specific antigen. The addition of a specific antibody or hormone to artificial lipid vesicles may serve as a mechanism to confer specificity to the vesicle in vivo.