Figure 5. The naive GAP50_40–48-specific CD8⁺ T cell repertoire is extremely large.

(A) CD8⁺ T cells specific for OVA_257–264, GP_33–41, GAP50_40–48, S20_318–326 and TRAP_130–138 were enriched from the spleens and macroscopic lymph nodes of naive C57Bl/6 mice and used to calculate the final numbers of tetramer⁺ cells indicated in each plot. Target cells were identified as CD8⁺ CD90.2⁺ CD11b⁻ CD11c⁻ B220⁻ tetramer(APC)⁺ tetramer(PE)⁺. Depicted numbers of naive precursors were calculated as mean ± SD from 11 mice for the GAP50_40–48-specific repertoire. Right panel: Vβ8.1/8.2 expression on naive GAP50_40–48-specific CD8⁺ T cells. (B) Sizes of the naive repertoires specific for various CD8⁺ T cell epitopes. The number of naive GAP50_40–48-specific precursors is represented as a range from 2,700–3,250 cells (total n = 11 mice). (C, D) Phenotypic characterization of naive GAP50_40–48-specific CD8⁺ T cells. (C) Expression of CD44 on naive GAP50_40–48-specific CD8⁺ T cells was compared with CD8⁺ T cells obtained from naive Tg OT-I and P14 mice. (D) Expression of CD5 on naive GAP50_40–48-specific CD8⁺ T cells was compared with total naive, non-GAP50_40–48-specific CD8⁺ T cells (left panel) and with naive Tg OT-I cells (right panel). Data represent two independent experiments (n = 4 mice/group). Bars depict mean ± SD.