UNIT 14.30 Measurement of Phagocytosis, Phagosome Acidification, and Intracellular Killing of Staphylococcus aureus

  1. Anna Sokolovska1,
  2. Christine E. Becker1,
  3. Lynda M. Stuart1,2

Published Online: 1 NOV 2012

DOI: 10.1002/0471142735.im1430s99

Current Protocols in Immunology

Current Protocols in Immunology

How to Cite

Sokolovska, A., Becker, C. E. and Stuart, L. M. 2012. Measurement of Phagocytosis, Phagosome Acidification, and Intracellular Killing of Staphylococcus aureus. Current Protocols in Immunology. 99:14.30:14.30.1–14.30.12.

Author Information

  1. 1

    Developmental Immunology/CCIB Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts

  2. 2

    The Broad Institute of MIT and Harvard, Cambridge, Massachusetts

Publication History

  1. Published Online: 1 NOV 2012
  2. Published Print: NOV 2012


Phagocytes are an important part of host defense, playing a critical role in innate immune responses against pathogens and in the initiation of adaptive immunity. One of the main characteristics of these cells is their ability to recognize and internalize invading microorganisms into a phagosome. The internalized microbe is rapidly delivered into a mature phagolysosome where it is killed and degraded. However, numerous pathogens have evolved complex mechanisms to manipulate these intracellular organelles to establish a survival niche. Here, we describe several methods to assess important properties of phagosomes in macrophages, such as phagocytosis, acidification of the phagosome contents during the maturation process, and the ability of phagosomes to inactivate and kill pathogens. Phagocytosis and phagosome acidification assays are FACS-based assays where labeled bacteria are used as probes to monitor internalization into a phagosome and to detect the pH of the phagosome environment. The killing assay is based on the counting of bacterial colonies after recovery of internalized bacteria from macrophages. Curr. Protoc. Immunol. 99:14.30.1-14.30.12. © 2012 by John Wiley & Sons, Inc.


  • phagocytosis;
  • phagosome acidification;
  • macrophages;
  • microbial killing;
  • gentamicin protection assay