IL-4Rα deficiency compromises the antigen-specific CD8⁺ T cell response to LCMV. (A–G) Intact WT and IL-4Rα KO BALB/cByJ mice (A–D and F) or mixed BM chimeras containing WT and IL-4Rα KO donor cells (E and G) were infected with LCMV Armstrong, and spleens were analyzed on day 7 after infection. (A–C) The frequency (A) and number (C) of NP_118–126/L^d tetramer–positive (Tet⁺) CD8⁺ T cells were measured, as was the number of total CD8⁺ T cells (B). (D–G) The frequency of NP_118–126/L^d tetramer–positive CD8⁺ T cells expressing the indicated pattern of T-bet/Eomes expression (D and E) or KLRG-1/CD127 expression (F and G) was determined in LCMV-infected WT and IL-4Rα KO mice (D and F) or mixed BM chimeras (E and G). (H and I) NP_118–126/L^d tetramer enrichment was used to enumerate the antigen-specific memory CD8⁺ T cells in WT and IL-4Rα KO mice (H) and mixed BM chimeras (I) at least 45 d after infection with LCMV. Error bars indicate mean ± SD. P-values are represented as *, P < 0.05; **, P < 0.01; ***, P < 0.001 by unpaired (A–D, F, and H) or paired (E and G) Student’s t test. (A–D and F) Data (n = 5 for WT, n = 5 for IL-4Rα KO) are representative of two individual experiments. (E and G) Data (n = 5 for mixed BM chimeras) are representative of two individual experiments. (H) Data are combined from two separate experiments (n = 6 for WT, n = 6 for IL-4Rα KO). (I) Data are combined from two separate experiments (n = 6 for mixed BM chimeras) and are representative of three individual experiments.