IMPAIRED NEUTROPHIL RESPONSE AND CD4(-HELPER-CELL-1 DEVELOPMENT IN INTERLEUKIN-6-DEFICIENT MICE INFECTED WITH CANDIDA-ALBICANS() T)

To define the role interleukin (IL) 6 in Candida albicans infection, I L-6-deficient mice were assessed for susceptibility to systemic or gas trointestinal infection, as well as for parameters of elicited T helpe r cell (Th) immunity. IL-6-deficient mice were more susceptible than w ild-type mice to either type of infection caused by virulent C. albica ns. In response to systemic challenge with a live vaccine strain of th e yeast, IL-6-deficient mice failed to mount Th1-associated protective immunity, but the resulting Th2-biased response could be redirected t o the Th1 phenotype by IL-10 neutralization. Severe impairment of the macrophage and neutrophil response to infection was observed in IL-6-d eficient mice, but administration of IL-6 would increase both neutroph il response and resistance to infection. IL-6 seems to oppose the Th2- promoting role of IL-10 in candidiasis, its early regulatory activity involving effects on neutrophil function.