Figure 1. Phenotypic heterogeneity of virus-specific CD4⁺ T cells is maintained during effector and memory differentiation.

2×10⁵ CD45.1⁺ LCMV-specific naive SMARTA transgenic CD4⁺ T cells were adoptively transferred into CD45.2⁺ naïve recipients that were then infected with 2×10⁵ PFU of LCMV Armstrong. FACS plots are gated on CD4⁺CD45.1⁺ SMARTA cells at the indicated timepoints relative to infection. A) Kinetics of splenic SMARTA CD4⁺ T cells. B) CXCR5, PD-1, ICOS, GL-7, Ly6c, and granzyme B analysis of naïve, effector, and memory SMARTA CD4⁺ T cells. C) Analysis of T-bet and Bcl6 expression. D) Analysis of Bcl6 and CXCR5 on effector (Day 8) and memory (Day 100–133) SMARTA cells in blood and spleen. E) Bcl6 MFI of CXCR5⁺ gated effector and memory SMARTA cells. Statistically significant p values are shown, and were determined using a two-tailed unpaired Students t test. F) The frequency of effector and memory SMARTA cells that are CXCR5⁺ and CXCR5⁻ in the following tissues: Spl=spleen; Bl=blood; iLN=inguinal lymph node; mLN=mesenteric lymph node; BM=bone marrow; Liv=liver; Lung, and IEL=intestinal intraepithelial lymphocytes. Graphs show the mean and s.e.m. N=3 mice at each timepoint. G) Plots of CD4⁺CD45.1⁺ gated SMARTA cells with gates indicating the Ly6c⁺CXCR5⁻ (blue), CXCR5⁺Ly6c^lo (red), and CXCR5⁺Ly6c^int (green) subsets. Chart indicates the number of each subset in spleen following infection (N≥3 at each timepoint). Error bars represent the SEM. See also Figure S1 and Table S1.