Among the cytokines, IL1β and TNFα play important roles both in innate and acquired immunity, such as the activation of phagocytic cells and the promotion of immune-related gene expressions in a series of immunoreactive cells both in mammals and fishes18, indicating that whether an animal is capable of inducing the expression of IL1β or TNFα in response to immune challenges reflects its infection resistance. The gene discussed is IL1B; the disease is infection.