The current study also identifies several factors, including IL-1α, MIP-1α, RANTES, IL-12(p40) and IL-12(p70) that are induced in aged mice but not young mice following infection (compared to PBS) and other factors, including IL-1β, IL-10, IL-13 and eotaxin that are specific to young mice. The gene discussed is CCL5; the disease is infection.