In the event of successful IEC infection, cell-mediated responses, including those driven by IFN-γ–producing CD4+ T cells, become critical for clearing immunity and eradication of established infection.6,10,19 Future vaccine development approaches ideally would robustly induce both mucosal (i.e., secretory IgA) antibody-mediated and cell-mediated responses. Here, CD4 is linked to infection.