Figure 1.

Spectratyping analysis of TCRVβ repertoire in WT and WAS^−/− mice. (A) Schematic of the TCR structure. The TCR is composed of an α and a β chain and the CDR3 regions determine most of the antigenic specificity. (B) V(D)J recombination results in varying CDR3 lengths. The size of the CDR3 region, comprising the segment junctions with a variable number of non-templated (N) nucleotides, differs between cells. (C) Spectratyping analysis. PCR products using TCRVβ specific primers (FWD) together with a Cβ primer (REV) were separated with capillary electrophoresis and analyzed for CDR3 transcript lengths using Peak Scanner™ Software v2.0. Each peak represents all cells expressing the same CDR3 length. In the healthy naïve T cell population, the CDR3 size distribution is Gaussian. (D) The thymocyte TCRVβ repertoires in one WT and one WAS^−/− mouse at 7 months of age. (E) Quantification of CDR3 size distribution. Non-linear regression analysis was performed on spectratyping data. An R² value of 1 indicates a perfect Gaussian distribution. (F) TCRVβ–CDR3 size distribution in thymus and spleen of three WT and three WAS^−/− mice at 7 months of age. R² values with mean ± SEM. **P = 0.0013.