TNF and infection: It is known that cytokines are involved in the host response to infection, with inflammatory cytokines (such as tumour necrosis factor-α (TNF-α), interleukin (IL) 1-β and IL-6) being expressed at the site of inoculation and T-cell associated cytokines (IL-2, IL-4 and interferon-γ (IFN-γ)) being expressed at lymph nodes [4,5].