Epitope repertoire of human CD4(+) T cells on tetanus toxin: Identification of immunodominant sequence segments

Sequence regions of tetanus toxin-forming CD4(+) cell epitopes in 8 HLA-disparate subjects were identified. Overlapping synthetic peptides corresponding to the complete tetanus toxin sequence were used to test, in a proliferation assay, unselected blood CD4(+) cells or CD4(+) cell lines propagated by stimulation with tetanus toroid, The CD4(+) cell lines recognized most peptides recognized by the blood CD4(+) cells and they recognized additional peptides, Their responses were stronger than those of unselected blood CD4(+) cells, Two peptides were recognized by all subjects: one largely overlapped a tetanus toxin sequence region previously identified as a ''universal'' T cell epitope, Thirteen other peptides elicited a CD4(+) cell response in 6 or 7 of the 8 subjects, and another 10 elicited responses in 5 subjects.