Which agent is most significant in the phagolysosome for the elimination of microorganisms?

Which agent is most significant in the phagolysosome for the elimination of microorganisms?

• A. Hydrogen ions
• B. Proteolytic enzymes
• C. Superoxides
• D. Hypochlorite ions

Answer: (D)

The main kill mechanism inside the phagolysosome is the myeloperoxidase (MPO) system. After the respiratory burst, neutrophils generate hydrogen peroxide, and MPO uses this H2O2 plus chloride ions to form hypochlorous acid, which exists as hypochlorite in physiological conditions. Hypochlorite is an extremely potent oxidizing and chlorinating agent that damages essential microbial components—inactivating proteins, lipids, and nucleic acids—and disrupts membranes, leading to rapid microbial death. While acidity, proteolytic enzymes, and other reactive oxygen species contribute to killing, the hypochlorite produced by MPO is the most significant antimicrobial factor in the phagolysosome.

The main kill mechanism inside the phagolysosome is the myeloperoxidase (MPO) system. After the respiratory burst, neutrophils generate hydrogen peroxide, and MPO uses this H2O2 plus chloride ions to form hypochlorous acid, which exists as hypochlorite in physiological conditions. Hypochlorite is an extremely potent oxidizing and chlorinating agent that damages essential microbial components—inactivating proteins, lipids, and nucleic acids—and disrupts membranes, leading to rapid microbial death. While acidity, proteolytic enzymes, and other reactive oxygen species contribute to killing, the hypochlorite produced by MPO is the most significant antimicrobial factor in the phagolysosome.