Respective rôle of lymphokines and monokines in macrophage activation.

When trying to manipulate the immune system in vivo by administration of immunoregulatory mediators, it is important to know which are the target cells of the injected mediator and what direct and indirect effects are likely to be obtained. It appears that some T cell lymphokines, such as interferon gamma (IFN-gamma), are able to induce a new state of differentiation in human monocytes, without necessarily triggering an ongoing function in such cells. In doing so, however, IFN-gamma primes macrophages for increased potential functions, such as monokine secretion. Monokines, in turn, participate directly in macrophage activation in an autocrine manner. Such cascades of events are important to analyse in order to optimize the rationale behind the administration of lymphokines and monokines in patients.