This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Chronic granulomatous disorder is due to defect in - 
Select and explain. 
A. B-cells, B. NADPH oxidase, C. IgA, D. T-cell
B: NADPH oxidase
Answer: B: NADPH oxidase 
Explanation: Chronic granulomatous disease is a fatal genetic disorder in which there is deficiency of NADPH oxidase. In these patients, leucocytes phagocytose invading bacteria normally but are unable to kill ingested micro organisms because engulfment of bacteria is not followed by activation of oxygen dependent killing mechanism. Reference : Baveja text book of microbiology, 4th edition, Pg no: 153 <\p>