High efficiency opsonin-independent phagocytosis ofCandida parapsilosisby human neutrophils

Candida species are associated with invasive fungal infections, and C. parapsilosis has become increasingly prevalent. As key antifungal effector cells, the function of human neutrophils confronting C. parapsilosis was investigated. We hypothesized that interaction between neutrophils and Candida species may not be uniform. Opsonins were omitted from these studies to understand the antifungal mechanisms at their most basic level. Human neutrophils underwent phagocytosis of C. parapsilosis with much higher efficiency than with C. albicans. Immunofluorescence assays with s-glucan specific antibody detected more surface exposed s-glucan on C. parapsilosis than C. albicans. However, blockade of the s-glucan receptor Dectin-1, reduced phagocytosis of C. albicans but not C. parapsilosis. Inclusion of excess β-glucan, mannan, or chitin also had no effect on phagocytosis of C. parapsilosis. Consistent with the differences noted in phagocytosis, neutrophils mediated damage to C. parapsilosis but not C. albicans in...