The MOST common pathogen in chronic granulomatous disease (CGD) is

Correct Answer: A

Rationale: Staphylococcus aureus is the most common pathogen in CGD, causing abscesses due to impaired oxidative killing by phagocytes.

Correct Answer: D

Rationale: Lymphocytes (B and T cells) are not phagocytic; they mediate adaptive immunity, unlike macrophages, neutrophils, and eosinophils which engulf pathogens.

Correct Answer: C

Rationale: Eosinophils are specialized for killing parasites, such as helminths, via granule release, not phagocytosis or histamine release.

Correct Answer: B

Rationale: The activation phase involves clonal expansion of lymphocytes with receptors matching the antigen.

Correct Answer: A

Rationale: BCRs on B cells can produce soluble antibodies, unlike TCRs or MHC molecules.