Tetramer-positive cells in multiparous and nulliparous human donors. The figure shows the proportion of HLA-A2/FIDSYICQV(HY) or HLA-A2/GLCTLVAML(EBV) tetramer⁺, CD8⁺ T cells logically gated from the live lymphocyte (PI negative) population, following weekly restimulations of PBMCs from a multiparous donor with HY-pulsed T2 cells, compared with PBMCs from a nulliparous donor restimulated with either HY- or EBV-pulsed T2 cells. Tetramer staining of the CD4 T-cell population from the same donors was a negative control (data not shown).