IMMUNE-RESPONSES TO V-ANTIGEN OF YERSINIA-PESTIS CO-ENCAPSULATED WITHIFN-GAMMA - EFFECT OF DOSE AND FORMULATION

Induction of systemic immune responses after intraperitoneal inoculati on of poly(L)lactide microspheres containing the V antigen of Yersinia pestis co-encapsulated with IFN-gamma were investigated. Serum antibo dy responses and T cell proliferative responses were measured in group s of Balb/c mice which were injected intraperitoneally with single or double emulsion preparations of either V/IFN-gamma or V alone in a ran ge of dose levels. Groups which received V antigen co-encapsulated wit h IFN-gamma produced higher V-specific antibody responses, predominant ly of the IgG1 isotype. Administration of 25 mu g V/IFN-gamma in a sin gle emulsion resulted in a significantly increased (p<0.05) splenic T cell proliferative response to V antigen compared with other formulati ons. Ii was concluded that IFN-gamma co-encapsulated with V antigen in poly(L)lactide microspheres acted as an adjuvant and increased antige n specific systemic immune responses. Therefore, cc-encapsulation with IFN-gamma may result in effective single nose vaccines by increasing the immunogenicity of the formulations. (C) 1998 Elsevier Science Ltd. All rights reserved.