HOMOGENEOUS PROCESSING AND PRESENTATION OF A RECOMBINED T-CELL EPITOPE IN INBRED MICE OF DIFFERENT NON-MHC GENETIC BACKGROUND

CD4(+) T cell responses are restricted by MHC class II-encoded glycopr oteins which display antigen-derived peptides, Chimeric MalE proteins expressing foreign T cell epitopes represent a potent means to induce immune responses for recombinant vaccine design. Here, we studied the influence of the non-MHC genetic background and of the processing hete rogeneity displayed by various APC types on the presentation of these chimeric proteins to T cells. For this purpose, the I-E(d)-restricted poliovirus CD4(+) T cell epitope was inserted into five different posi tions on the surface of MalE protein and the immunogenicity of the rec ombined T cell epitope was determined in different inbred mice. Immuni zation of several mouse strains expressing I-E(d) with these chimeric proteins induced poliovirus-specific T cell response with four out of five constructs. In vitro presentation studies of the recombined epito pe to specific T cells indicated that for a given chimeric protein the fine processing is conserved, whatever the non-II-a genetic backgroun d of APC or the type of APC. Our results show that the insertion site in MalE modulates the immunogenicity of the recombined T cell epitope, but this phenomenon is only related to the MHC genetic background. (C ) 1996 Academic Press, Inc.