The attachment (G) glycoprotein of respiratory syncytial virus contains a single immunodominant epitope that elicits both Th1 and Th2CD4+ T cell responses

BALB/c mice immunized with a vaccinia virus expressing the attachment (G) glycoprotein of respiratory syncytial virus (RSV) develop a virus-specific CD4(+) T cell response that consists of a mixture of Thf and Th2 CD4(+) T cells following intranasal infection with live RSV, Recent work has shown that both Th1 and Th2 CD4(+) T cells are elicited to a single region comprising aa 183-197 of the G protein. To more precisely define the CD4(+) T cell epitope(s) contained within this region, we created a panel of amino- and carboxyl-terminal truncated as well as single alanine-substituted peptides spanning aa 183-197, These peptides were used to examine the ex vivo cytokine response of memory effector CD4(+) T cells infiltrating the lungs of G-primed RSV-infected mice. Analysis of lung-derived memory effector CD4(+) T cells using intracellular cytokine staining and/or ELISA of effector T cell culture supernatants revealed a single I-E-d-restricted CD4(+) T cell epitope with a core sequence mapping to aa 185-193, In addition, we examined the T cell repertoire of the RSV G peptide-specific CD4(+) T cells and show that the CD4(+) T cells directed-to this single immunodominant G epitope use a restricted range of TCR V beta genes and predominantly express V beta 14 TCR.