Wagstaffe, Helen, Scott Jones, Marina Johnson, and David Goldblatt. Opsonophagocytic Killing Assay to Measure Anti-Group A Streptococcus Antibody Functionality in Human Serum. In Bacterial Vaccines, pp. 373-386. Humana, New York, NY (2022).
…≤ 1 month. 10. Opsonisation buffer (OPS buffer), 5ml FCS, 40ml 1x HBSS (+Ca/Mg), 5ml 1% gelatin solution. Prepare on day of assay and discard after use. 11. HL-60 Cells, ATCC. 12. Baby rabbit complement, Pel-Freez. Page 5 of 22 3. Methods 3.1. HL-60 Cells. HL-60 cells are promyelocytic leukaemia cells which are differentiated to a neutrophil-like cell with 0.8% dimethylformamide (DMF). All cell culture is to be…
Abstract
The opsonophagocytic killing assay (OPKA) is designed to measure the functionality of strain-specific antibodies and, therefore, assess protective immunity or the immunogenicity of Group A Streptococcus (GAS) (type A Streptococcus pyogenes) vaccines. Opsonization of GAS for phagocytosis is an important mechanism by which antibodies protect against disease in vivo. The Opsonophagocytic Index or Opsonic Index (OI) is the estimated dilution of antisera that kills 50% of the target bacteria. Here, we describe the protocol of the standardized GAS OPKA developed by Jones et al., 2018.