IDENTIFICATION OF HELPER T-CELL EPITOPES OF DENGUE VIRUS E-PROTEIN

The T cell proliferative response to dengue 2 (Jamaica) E-glycoprotein (495 amino acids) was analyzed in vitro using either killed virus or E-protein fragments or synthetic peptides. Inactivated dengue virus st imulated dengue-specific lymph node (LN) CD4+T cell proliferation in B ALB/c (H-2d), C3H (H-2k) and DBA/1 (H-2q) but not in C57BL/6 (H-2b) mi ce. Moreover, LN cells from dengue-virus primed BALB/c mice proliferat ed in vitro in response to three purified non-overlapping E-protein fr agments expressed in E. coli as polypeptides fused to trpE (f22-205, f 267-354, f366-424). To further determine T cell epitopes in the E-prot ein, synthetic peptides were selected using prediction algorithms for T cell epitopes. Highest proliferative responses were obtained after i n vitro exposure of virus-primed LN cells to peptides p135-157, p270-2 98, p295-307 and p337-359. Peptide p59-78 was able to induce specific B and T cell responses in peptide-primed mice of H-2d, H-2q and H-2k h aplotypes. Two peptides p59-78 corresponding to two dengue (Jamaica an d Sri Lanka) isolates and differing only at position 71 cross-reacted at the B but not at the T cell level in H-2b mice. This analysis of mu rine T helper cell response to dengue E-protein may be of use in dengu e subunit vaccine design.