How is HOCl made and used in white blood cells?

Microbes are engulfed by a type of white blood cell, neutrophils, by phagocytosis into a membrane bound “bag” or phagosome (or endolysosome).

Once inside the cell, the phagosome fuses with a lysosome to form a phagolysosome.

The encapsulation allows membrane bound enzymes to produce a highly  microbiocidal internal environment.

The microbe is annihilated and the residues of its destruction are discharged from the cell.

On the phagolysosome membrane surrounding the engulfed microbe, the following reactions take place, resulting in the formation of HOCl in the phagolysosome lumen. While the cell cytoplasm is neutral to slightly alkaline, the lumen of the phagolysosome is  maintained at about pH 5.0, which is close to optimal for HOCl stability and biocidal action.