Variability of the human Vβ repertoire restriction between chimera. Fresh donor's PBL and splenic cells from chimeras C5, 19, 24, and 34, killed at day 65, 70, or 77, were treated as described in Fig 2 using specific primers for Vβ7⁺ and Vβ17⁺ subsets. Analysis of CDR3 size distribution was performed as described in Fig 2 (left part of the figure). Next, a run off was performed on the same Vβ/Cβ PCR products using fluorescent specific primers to the 13 human Jβ segments. Analysis of the Jβ segment usage by Vβ7⁺ and Vβ17⁺ T cells was performed for CDR3 size equal to 11 and 9, respectively (right part of the figure). Hatched boxes correspond to the detection of the corresponding Jβ (annoted BJ) segment associated with the tested Vβ (annoted BV) segment.