Induction of tolerance by haptenated liposomes carrying mouse erythrocyte membrane glycoprotein.

Membrane sialoglycoprotein (GP) of mouse erythrocytes were incorporated into artificial membranes of liposomes which also contained DNP-aminocaproylphosphatidylethanolamine hapten. The liposomes were tested for their potential to modulate the anti-hapten antibody response in mice as a plausible model of haptenated isologous erythrocytes which is known to be a potent tolerogen. Repeated intravenous inoculation with DNP-liposomes carrying mouse GP resulted in a significant suppression of splenic plaque-forming cells and serum antibody produced in the recipient mice against the subsequent immunization with DNP-KLH in saline or DNP-HGG in Freund's complete adjuvant, in a strictly hapten-specific fashion. The suppression was long-lasting, and the secondary response to DNP-KLH given over a month later was also affected. DNP-liposomes without GP, or those with rabbit GP, exhibited little or no suppressive effect. The observed capacity of mouse GP-bearing DNP-liposomes was reminiscent of that of haptenated mouse erythrocytes in that only the IgG response, but not the IgM response, was suppressed.