Both TMEV-susceptible (e.g., SJL/J) and TMEV-resistant (e.g., C57BL/6J) inbred mouse strains mount a strong pro-inflammatory cytokine response within the CNS during the acute phase of infection, for example as shown by increased transcript levels for cytokines IFN-γ, IL-1, IL-6, IL-12p40, and TNF-α. This evidence concerns the gene IL1A and infection.