While leukocyte-derived ACh effects in the spleen have been shown previously to require T cell-mediated ACh production55,56, T cell-specific deletion of ChAT (Chatfl/fl- LckCre+/−) did not affect influenza virus loads at 1 dpi (Fig. 2h), consistent with their low frequencies in all tissues prior to infection (Extended Data Fig. 2). Here, CHAT is linked to infection.