EGR2 and viral infectious disease: The lack of Tfh cells was not due to a failure to activate EGR2/3-deficient CD4 T cells because EGR2/3-deficient CD4 T cells did not have defects in activation marker expression, as indicated by CD44high cell frequency (Fig. 2D), or effector cytokine expression (Fig. 2E) in response to viral infection.