The major function of signalling molecules is to attract additional leukocytes from the circulation to the site of infection (IL1β, IL8, IL17) [33,34], to increase general resistance of epithelial cells to the infection (IL22) [35], or to stimulate macrophages for NO radical production and Salmonella inactivation (IFNγ) [36]. This evidence concerns the gene CXCL8 and infection.