CD4 and infection: Notably, the temporal dynamics of lymphocyte infiltration during ARV infection exhibit a distinct pattern: acute infection (2–6 days post-infection, or dpi) is characterized by a predominant CD8+ T-cell response, subacute infection (8–14 dpi) involves both CD4+ and CD8+ T cells as well as IgM+ B cells, and chronic infection (>14 dpi) is associated with CD4+ T-cell infiltration and limited B-cell activity.