CMV-specific CD4 T cells are oligoclonal. CMV-specific T cells were found among T cells expressing different T-cell receptors. (A) Shown are the respective specific T cells among cells expressing TCR-Vβ5.2, -Vβ8.0, -Vβ13.1, -Vβ16, -Vβ20, and -Vβ21.3 in a representative example (individual #0320). A particularly high percentage of CMV-specific T cells express TCR-Vβ13.1 or -Vβ16, whereas no specific T cell expresses TCR-Vβ8.0. The two numbers in each diagram indicate the percentages of TCR-Vβ-positive cells among all CD4 T cells and among CMV-specific CD4 T cells, respectively. (B) TCR-Vβ distribution among CMV-specific CD4 T cells in different individuals. + and / indicate the presence or absence, respectively, of IFN-γ-positive CD4 T cells within the respective T-cell population bearing a particular TCR-Vβ subunit.