What substances in segmented neutrophils are important for intracellular killing of bacteria?

a. Alkaline phosphatase and halides
b. Myeloperoxidase and superoxide
c. Collagenase and hydrogen peroxide
d. Acid phosphatase and anions

ANS: B
Bacteria killing is a complex mechanism, requiring activation of the neutrophil, ingestion of the bacterium, and incorporation into a phagosome. Cytoplasmic granules fuse with the lysosome and dump their contents. Myeloperoxidase, halides, hydrogen peroxide, and the formation of superoxide and oxygen radicals are all instrumental for killing. Also critical for killing is activation of proteinases such as cathepsin G.