Because bak-null mice showed a reduced gastric corpus epithelial cell apoptotic index following infection compared with C57BL/6 mice (Fig. 7, A and B) but displayed no differences in inflammatory infiltrate at 6 and 48 wk following H. felis infection (Fig. 4, C and E) and because H. felis-induced pathology is thought to be mediated by an increase in Th1 cytokines, we assessed the direct effects of three cytokines known to be expressed in abundance following H. felis infection (10) on isolated gastric glands from C57BL/6 and bak-null mice. The gene discussed is BAK1; the disease is infection.