Differential binding of lectins IL-2 and CSL to candida albicans and cancer cells

The demonstration that interleukin 2 (IL-2) is a lectin specific foroligomannosides allows to understand a new function for this cytokine: as abifunctional molecule when bound to its receptor ss, IL-2 associates thelatter which the CD3/TCR complex, interacting with oligosaccharides of CD3through its carbohydrate-recognition domain (Zanetta et al. , 1996,Biochem. J., 318, 49-53). This induces the tyrosine phosphorylation of theIL-2R beta by ++p56(lck) , the first step of the IL-2-dependent signaling.Since this specific association is disrupted in vitro by oligomannosideswith five and six mannose residues, we made the hypothesis that pathogeniccells or microorganisms could bind IL-2, consequently disturbing the IL-2-dependent response. This study shows that the pathogenic yeast Candidaalbicans (in contrast with nonpathogenic yeasts) binds high amounts of IL-2as did cancer cells. In contrast with cancer cells, yeasts do not bind theMan6GlcNAc2-specific lectin CSL, an endogenous "amplifier of activationsignals" (Zanetta et al. , 1995, Biochem. J., 311, 629-636).