While IL-4 is known to induce Th2 responses (Himmelrich et al., 2000, Radwanska et al., 2007), previous studies have also shown that the administration of recombinant IL-4 within 8 hours post-infection with L. major led to increased IL-12 mRNA expression by dendritic cells in vivo and rendered mice resistant to infection (Biedermann et al., 2001). This evidence concerns the gene IL4 and infection.