Molecular analysis of the Vβ repertoire of human T-lymphocyte receptors before and after engraftment. RNA was isolated from single-cell suspensions of PB, BM, and spleen as described in “Materials and methods.” Patterns of Vβ families of T lymphocytes in the initial population of huPBMCs and after engraftment in PB, BM, and spleen, measured as the relative fluorescence intensity, showed a Gaussian distribution indicative of a polyclonal repertoire of T-cell receptors. Vβ2 and Vβ22 are depicted as representative examples. Other Vβ families showed similar patterns.