Figure 5. Viral Infection Induces Increased Number of miR-181a-Deficient Memory CD4 T Cells.

(A) Equal numbers of congenically marked WT and miR-181a^−/−YFP⁺ SMARTA CD4 T cells were co-transferred into B6 mice subsequently infected with LCMV 1 day later. Representative flow plots of SLAM and CXCR5 expression by WT and miR-181a^−/− SMARTA CD4 T cells (left) and dot plots of the total numbers of SLAM⁺ Th1 and CXCR5⁺ Tfh SMARTA CD4 T cells in the spleen (right) on day 8 after infection.

(B) Representative flow plots of SLAM and CXCR5 expression by IA^b GP66 tetramer⁺ YFP⁺ CD4 T cells from LCMV-infected WT and miR-181a^−/− mice (left) and dot plots of the total numbers of Th1 and Tfh tetramer⁺ CD4 T cells in the spleen (right) on day 8.

(C–E) Numbers of IA^b GP66 tetramer⁺ YFP⁺ CD4 T cells in the spleen at indicated time points (C) and in mesenteric and inguinal lymph nodes on day 85 (D). Representative flow plots of IA^b GP66 tetramer⁺ cells gated on YFP⁺ CD4 T cells (E, left), representative histogram of tetramer binding intensity (middle), and dot plot of tetramer MFI (right). Filled gray in the histogram indicates naive CD4 T cells.

(F–H) Dot plots show MFI of indicated cytokines (F), the proportion of cells co-producing IFNγ, IFNα, and IL-2 (G) and the effective GP61 peptide concentration required to elicit a half-maximal IFNγ production (H) by GP61-specific YFP⁺ CD4 T cells in the spleen on day 85 after LCMV.

Unless stated otherwise, data are representative of two independent experiments with 4–5 mice per group (A and B) or pooled from two independent experiments with 6–9 mice per group (C–H). Data are presented as means. Statistical significance by two-tailed paired (A) or unpaired (B–H) t test. *p < 0.05; **p < 0.01; ***p < 0.001; NS, not significant.