ANTIGEN INCORPORATION INTO LIPOSOMES RESULTS IN THE ENHANCEMENT OF IL-4 AND IGG1 SECRETION - EVIDENCE FOR PREFERENTIAL EXPANSION OF TH-2 CELLS

Liposomes have been used to modify the immunological behaviour of a nu mber of antigens. The present study was designed to evaluate the effec t of liposomization of ovalbumin on the induction of Th-1- and Th-2-ce ll response by monitoring the secretion of lymphokines and IgG isotype s. Liposomes having varied physicochemical properties (positively and negatively charged, neutral and pH sensitive) were used for this purpo se. Ovalbumin delivered in this way induced preferential secretion of IL-4 and production of antigen-specific IgG1 isotypes. This was observ ed irrespective of the surface charge properties of the liposomes. Fur ther, the concentration of antigen required for the activation of Th c ells was 10(2)- to 10(3)-fold lower after encapsulating it in liposome s. These results suggest that liposomes may prove useful adjuvants to prime Th2-like immune responses.