Interestingly, PD-1 expression strongly correlated with OX40 expression during both acute and persistent LCMV infection suggesting that the sustained OX40 expression during LCMV cl13 infection is a consequence of ongoing antigen recognition (Fig. 4C) and in line with prior data showing that TCR signaling is sufficient to induce OX40 on T cells [28]. The gene discussed is TNFRSF4; the disease is infection.