ANALYSIS OF T-HELPER CELL RESPONSE TO GLYCOPROTEIN-H (GPUL75) OF HUMAN CYTOMEGALOVIRUS - EVIDENCE FOR STRAIN-SPECIFIC T-CELL DETERMINANTS

The proliferative response of helper T cells against glycoprotein H (g H; gpUL75) of human cytomegalovirus (HCMV) was determined in T cell li nes from 5 healthy HCMV-seropositive donors. A differential response i n two lines was noted when gH from strain AD169 or Towne was used as a ntigen. T cell-reactive domains between aa 15 and 510 were identified using beta-galactosidase fusion proteins containing overlapping fragme nts of gH, and they were confirmed with synthetic peptides as stimulat ing antigen. T cell proliferation was observed with antigens containin g aa 34-51, 111-142, 284-302, 324-342, and 454-510 of gH. None of the determinants stimulated all donors. The T cell epitope defined by aa 3 4-51 is located in close proximity to a strain-specific dominant B cel l epitope; however, no strain dependence for this T cell determinant w as observed, In contrast, the dominant T cell response against aa 284- 302, which was observed in three T cell lines, was strain specific.