CD4 and infection: These results were confirmed by the CRISPR/Cas9-mediated deletion of Plekho1 (Plekho1-CRISPR) in naïve OT-II cells in the PR8-OVA infection model (Supplementary Fig. 7a), suggesting that Plekho1 does not affect early phase CXCR5+CD4+ T cell development but rather plays a later, stage-specific role in regulating the PD-1hiCXCR5hi GC-Tfh cell differentiation.