Biological activity of interleukin-2 bound to Candida albicans.
The lymphokine interleukin-2 (IL-2), which is necessary for the generation of an optimal cell-mediated immune response, has recently been shown to have lectinlike properties, with specificity for high-mannose groups. Therefore, the ability of IL-2 to bind to the mannose-rich fungus Candida albicans was examined. Heat-killed fungi preincubated with IL-2 stimulated, in a dose-dependent manner, proliferation of the IL-2-dependent cell line CTLL20. Soluble mannan, which is rich in exposed mannose groups, inhibited binding of IL-2 to C. albicans by approximately 60%, suggesting that the lectinlike properties of IL-2 are partially responsible for its fungal binding capacity. Binding of IL-2 to fungi appeared to be reversible, as C. albicans preincubated with IL-2 stimulated CTLL20 proliferation even when the fungi and cells were separated by an 0.4-microns-pore-size membrane. The lymphoproliferative response of normal human peripheral blood mononuclear cells to C. albicans was augmented when the fungus was preincubated with IL-2. Binding of 125I-IL-2 could not be inhibited by unlabeled IL-2, suggesting the absence of high-affinity receptors on C. albicans for IL-2. While the in vivo relevance remains to be determined, these data demonstrate that IL-2 can bind to C. albicans in vitro and thereby influence the host response to this medically important fungus.
Treseler
C B
CB
Evans Memorial Department of Clinical Research, Boston University Medical Center, Massachusetts 02118.
Maziarz
R T
RT
Levitz
S M
SM
D002176:Candida albicans / Q000378:metabolism* / Q000472:pathogenicity; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism* / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000502:physiology; D008351:Mannans / Q000494:pharmacology; D015375:Receptors, Interleukin-2 / Q000378:metabolism
D007376:Interleukin-2; D008351:Mannans; D015375:Receptors, Interleukin-2