Potential clinical applications of interleukin-12.

Interleukin-12 is a central modulatory cytokine with potent effects on the development and differentiation of the cellular immune response. Because of its biologic activities, interleukin-12 could either mediate or contribute to the control of a large range of critical world-wide pathologic conditions, including infectious diseases and cancer. Its potential efficacy has been demonstrated in several animal models of intracellular pathogens and tumors, as well as in vitro in some human pathologies. As an adjuvant, interleukin-12 appears to be useful for inducing a protective immune response in different animal models. However, its potential toxicity and complex regulation indicate that clinical trials must proceed with caution. Thus its prophylactic and therapeutic value may reside in our ability to minimize toxicity and simultaneously deliver this cytokine to immunologically relevant sites.