The protective role of interleukin-18 in Salmonella infection.

: Since its derivation, much has been learned about the proinflammatory inducing cytokine interleukin-18, and its role in resolving infectious diseases. Studies to date that examined interleukin-18 have shown that endogenously induced interleukin-18 plays an important protective role in some viral and bacterial infections. However, interleukin-18 has a limited role in protective immunity to Salmonella infections, and is secondary to the protective role of interleukin-12. This lack of sensitivity to interleukin-18 may be in part related to the dependence on interleukin-12 for interleukin-18 receptor expression and to the nanomolar concentrations that are required. Nonetheless, an understanding of how some pathogens have evolved to circumvent interleukin-18 and of how interleukin-18 can be effectively induced are essential to our ability to develop better vaccines against enteric pathogens.