To study possible effects of Salmonella on T cell activation during systemic phase of infection in which this pathogen is largely present in spleen and liver, C57BL/6 mice were infected intraperitoneally with S. Typhimurium and on day 5, mice were injected with anti-CD3 antibody and cytokines IL-2 and IFN-γ were determined in sera. This evidence concerns the gene IL2 and infection.