BAFFR^-/- mice have reduced T cell responses early after WNV infection but their CD4⁺ and CD8⁺ T cells respond normally to WNV-specific peptides <i>in vitro</i>.

<p><i>A-F</i>, Spleens from WT and BAFFR^-/- naïve mice or from mice 7 days after s.c. WNV infection were harvested, and cell populations were determined by flow cytometry. In <i>A</i>, absolute numbers of CD4^<b>+</b> and CD8^<b>+</b> T cells. In <i>B</i>, CD4^<b>+</b> T and CD8^<b>+</b> T cells subpopulations were determined as described in the <b><i>Methods</i></b> and are defined as: naïve (Tn), central memory (Tcm) and effector (Teff) T cells. WNVE-tetramer+ CD4^<b>+</b> T cells and NS4b-tetramer+ CD8^<b>+</b> T cells are shown as frequencies in representative dot plots (<i>C</i> and <i>D</i>) and as absolute cell numbers (<i>E</i>). In <i>A</i>, <i>B</i> and <i>E</i>, graphs summarize data from three independent experiments (N = 9), except for NS4b Tetramer⁺ CD8^<b>+</b> T cells where the graph summarizes data from two independent experiments (N = 6). In <i>F</i>, naïve or WNV infected splenocytes were stimulated with 1 μM WNV E_641-655 peptide (<i>left panel</i>) or 1 μM NS4B H-2D peptide (<i>right panel</i>) for 6 h <i>in vitro</i>. Reported are cell numbers of IFNγ⁺ or TNFα⁺ CD44⁺ CD4^<b>+</b> T cells (<i>left panel</i>) or CD8^<b>+</b> T cells (<i>right panel</i>) from one representative out of two independent experiments with three mice per group. In <i>A</i>, <i>B</i>, <i>E</i> and F bar graphs show means ± SEM; * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001, as determined by one-way ANOVA corrected with Holm-Sidak method for multiple comparisons.