A brown pigmentation indicated that TLR4 immunohistochemical staining within the neocortex of brains of mice infected by Acanthamoeba strain Ac55 (Fig. 3e, i, m, q) was the highest at 2 dpi (Fig. 3e) and markedly decreased during the time of infection (Fig. 3i, m, q). The gene discussed is TLR4; the disease is infection.