Our previous study found that compared with both BALB/c and CBA/J mice, ocular infection of C57BL/6 (B6) mice with T. gondii resulted in severe inflammatory lesions and high numbers of parasites in eye tissue, and higher serum levels of gamma interferon and tumor necrosis factor alpha (TNFα), indicating that genetic factors of the host are critical in determining susceptibility to experimental OT in murine models (Lu et al., 2005). Here, TNF is linked to eye infection.