Opsonophagocytosis Assay Using Flow-Cytometry

We describe the development of a flow-cytometric-based opsonophagocytosis (OP) assay that is capable of looking at antigen-specific antibodies, that is, complement-dependent, not complement-mediated. Using the OP assay we are able to look at uptake of bacteria by neutrophils simultaneously with oxidative burst within the cell. This assay using human donor peripheral blood polymorphonuclear cells (PMNs) is rapid, reproducible, and specific. Other OP assays described use HL-60 cell lines that are technically more difficult to use and require tissue culture facilities (1 ).