Comparison of CDR3 size distribution of the human Vβ subsets before and after engraftment. RNA extraction from fresh donor's PBL or from spleen cells of chimera C5, killed at day 65 postengraftment, PCR and run off reactions were performed as described in Materials and Methods. Patterns represent the distribution, measured as relative fluorescence intensity, of the aa size of the CDR3 for the PCR reaction products obtained for each Vβ subset studied. Patterns on the bottom left correspond to chimera's profiles and patterns on the top right correspond to fresh donor's profiles. Each peak corresponds to a defined CDR3 size.