Ch. Mody et al., INTERLEUKIN-15 INDUCES ANTIMICROBIAL ACTIVITY AFTER RELEASE BY CRYPTOCOCCUS-NEOFORMANS STIMULATED MONOCYTES, The Journal of infectious diseases, 178(3), 1998, pp. 803-814
A newly described cytokine, interleukin (IL)-15, shares many activitie
s with IL-2; however, little is known about the stimuli for release of
IL-15, and its role in antimicrobial host defense has not previously
been demonstrated. This study found that Cryptococcus neoformans is a
potent stimulus for the release of biologically active IL-15 from mono
cytes. Both IL-15 and IL-2 made significant contributions to lymphocyt
e proliferation and lymphocyte-mediated anticryptococcal activity to e
ncapsulated and acapsular C. neoformans. IL-15 restored lymphocyte pro
liferation and anticryptococcal activity that had been abrogated by bl
ocking IL-2. IL-15 also enhanced the anticryptococcal activity of lymp
hocytes but did not enhance the activity of monocytes. This suggests t
hat IL-15 and IL-2 cooperate for lymphocyte activation and proliferati
on in vitro and demonstrates that IL-15 can induce antimicrobial activ
ity, Taken together, these data suggest that microbes, and in particul
ar C. neoformans, are an important stimulus for IL-15 and that IL-15 m
ay have an important role in induction of antimicrobial effector mecha
nisms.