EFFECT OF IL-4 AND IL-12 LIPOSOMAL FORMULATIONS ON THE INDUCTION OF IMMUNE-RESPONSE TO BOVINE HERPESVIRUS TYPE-1 GLYCOPROTEIN-D

Activation of different T-helper (Th) responses following immunisation has profound and specific influences on the development of the immune response and on the ability of a vaccine to confer protection. Since cytokines are capable of influencing the stimulation of distinct T-cel l responses, their encapsulation in vaccines should modulate antigen-s pecific immune responses. Unfortunately, the use of cytokines in vivo is hampered by their rapid clearance and inactivation. One possible so lution to this problem is the use of liposomes to entrap both cytokine s and antigen, This approach will not only protect the cytokine but wi ll also deliver the two components simultaneously to the same site. Th e authors examined, therefore, the immune responses elicited by system ic immunisation of mice with liposome formulations containing a trunca ted form of bovine herpesvirus type-1 glycoprotein D (tgD) together wi th IL-4 or IL-12, Subcutaneous immunisation with liposomes containing tgD and IL-12 significantly enhanced the induction of antigen-specific cellular and humoral immune responses, These responses were character ised by an increase in IFN-gamma secreting cells and the induction of tgD-specific IgG2a antibodies. In contrast, encapsulation of IL-4 into tgD-liposomes did not enhance the humoral immune response to go but s ignificantly influenced the development of antigen-specific IL-4 secre ting cells, bur results indicated that encapsulation of IL-12 into the liposomes was necessary for the systemic adjuvant effect and demonstr ated the feasibility of using liposome technology and cytokines to man ipulate the development of different antigen-specific Th subsets in vi vo. (C) 1997 Elsevier Science Ltd.