Characterization of T-cell reactive epitopes in glycoprotein g of herpes simplex virus type 2 using synthetic peptides

We have previously shown that the CD4+ T-cell response to herpes simplex virus type 2 glycoprotein G-2 is type-specific and can thus be used to evaluate herpes simplex virus type 2-specific T-cell responses in individuals with a concomitant herpes simplex virus type 1 infection. In this study we have followed the glycoprotein G-2-specific T-cell responses over time, and also tried to identify T-cell epitopes in the membrane bound portion and the secreted portion of glycoprotein G-2 using synthetic peptides spanning the whole amino acid sequence of glycoprotein G-2. We found that the magnitude of the glycoprotein G-2-specific response varied considerably in infected individuals over time, even though all patients responded to at least one of the two glycoproteins at all time-points examined. We could also document strong T-cell responses to synthetic peptides from the secreted glycoprotein G-2 but only low responses to synthetic peptides corresponding to sequences from the heavily glycosylated membrane-bound glycoprotein G-2. We were able to map an immunogenic region (amino acid 31-125) within the secreted glycoprotein G-2. This region of the glycoprotein induced proliferative responses in 47% of the herpes simplex virus type 2-infected individuals. However, we were not able to identify any universal T-cell epitope.