The following antibodies were used for staining: CD4 BUV395, CD8α BUV737 (BD); CD5 PerCp-Cy5.5, CD25 PE or APC, CD44 FITC or Pacific Blue, CD45.2 PE, CD62L APC, CD69 APC, TCRβ Pacific Blue, Vα2 PE or Pacific Blue, CXCR5-biotin, PD-1 FITC, SLAM PE-Cy7, CD95 PE-Cy7, GL-7 FITC (Biolegend); B220 efluore780, CD8α efluore780, ZAP70 Alexa488, Strepavidin-A647 (Life Technology); GP66 tetramer PE or APC (NIH Tetramer Core Facility). The following antibodies were used for immunoblot analysis: ZAP70 (clone 1E7.2) (36 (link)); ZAP70-pTyr319 (clone 65E4), LAT-pTyr191, Erk1/2, Erk1/2-pThr202/pTyr204, and PLCγ-pTyr183, all from Cell Signaling Technology; anti-phosphotyrosine (4G10), PLCγ (Sigma-Aldrich), LAT (clone FL-233, Santa Cruz Biotechnology), FLAG (clone M2, Sigma-Aldrich), and GAPDH (clone 6C5, Santa Cruz Biotechnology).