Modifications of the Vβ subset representation in chimeras. (A) The percentage of Vβ⁺ (BV) CD3⁺ among total CD3⁺ T cells from fresh PBL and from the spleen of 9 chimeras killed at times indicated was determined by FACS analysis using anti-CD3 MoAbs and MoAbs specific for several regions of the human TCR. (B and C) The same analysis was performed on human CD4⁺ (B) and CD8⁺ (C) T cells from donor and from 3 chimeras.