Overlapping TCR repertoire in FCRL3 ⁺ and FCRL3 ⁻ cells. (A) Number of unique productive TCR Vβ rearrangements (left) and Simpson’s clonality index (right) in sorted CD8⁺ FCRL3⁺ and CD8⁺ FCRL3⁻ memory T cell subsets from three healthy donors (D1–D3) (initial input, 5 × 10⁵ cells per subset). Each dot represents one donor (N = 3). Mean ± SD. (B) TCR Vβ gene family usage by CD8⁺ FCRL3⁺ (upper panel) and CD8⁺ FCRL3⁻ memory T cells (lower panel) in three healthy donors. Slices in the chart represent different Vβ gene families, and their size is proportional to the frequency of clonotypes using that segment. The color-coded legend is reported for the 26 different Vβ gene family. The total number of clonotypes is indicated at the center of the pie chart. (C) Percentage of clonotypes bearing the same CDR3β length defined by the number of nucleotides. The CDR3β length of TCR Vβ clonotypes from CD8⁺ FCRL3⁺ and CD8⁺ FCRL3⁻ memory T cells is shown in lavender and gray, respectively. Each dot represents one donor (N = 3). Mean ± SD. (D) Pairwise comparison of TCR Vβ clonotype frequency distribution in CD8⁺ FCRL3⁺ memory T cells (x axis) and CD8⁺ FCRL3⁻ memory T cells (y axis) from N = 3 donors. Frequencies are shown as a percentage of productive templates. Each dot indicates a unique TCR Vβ clonotype. Dots outside the dashed lines represent clonotypes that were found in only one of the two samples and that were assigned an arbitrary frequency value for graphical purposes. The total number of clonotypes is indicated in the x and y axes. Values in the upper right corner represent the number of clonotypes shared between two samples. (E) Unique and shared TCR Vβ clonotypes between CD8⁺ FCRL3⁺ and CD8⁺ FCRL3⁻ memory T cells in N = 3 donors. Shown are the percentage of clonotypes based on the Jaccard index (left) and their cumulative frequency (right). Data underlying this figure can be found in Data S4.