Opsonophagocytosis of C. parapsilosis and reference strains C. albicans , C. neoformans , S. aureus and E. coli by human polymorphonuclear (PMN) cells. Microorganisms were labelled with fluorescein isothiocyanate (FITC) and preincubated in the absence (control) or presence of 20% mannose-binding lectin (MBL)-deficient serum supplemented with 5 μg/mL human purified MBL, for 20 min. The yeast:phagocyte ratio was 2:1. Phagocytosis was analyzed by the use of flow cytometry and expressed as percentage of microorganisms-ingested PMN. Data are the mean ± SEM of 3 separate experiments. *P < 0.05 and ** P< 0.005 unpaired Student's t test of phagocytosis % gated.