This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
The most efficient bactericidal system of neutrophils is 
Select and explain. 
A. H2O2-MPO-Halide, B. NADPH oxidase, C. Lysozyme, D. Reactive nitrogen species
A: H2O2-MPO-Halide
Answer: A: H2O2-MPO-Halide 
Explanation: H2O2-MPO-halide system is the most efficient bactericidal system of neutrophils H2O2 is not able to efficiently kill microbes by itself. the azurophilic granules of neutrophils contain the enzyme myeloperoxidase (MPO), in the presence of a halide such as Cl-, conves H2O2 to hypochlorite(OCl2-) which is a potent antimicrobial agent that destroys microbes by halogenation (in which the halide is bound covalently to cellular constituents) or by oxidation of proteins and lipids (lipid peroxidation). Robbins 9th ed page 79