An example of a cytokine produced by activated macrophages with a major role on the innate immune response is:

Correct Answer: B

Rationale: TNF (tumor necrosis factor) from macrophages drives innate inflammation, unlike IL-2 (T cell growth), IL-4 (Th2), or IL-17 (Th17).

Correct Answer: B

Rationale: CTLA-4 on activated T cells binds B7 with higher affinity than CD28, inhibiting T cell activation.

Correct Answer: A

Rationale: Paratope is the antibody site, not epitope ; epitope , IgG bivalence , and heavy chain class are true.

Correct Answer: C

Rationale: Plasma cells secrete antibodies; memory cells persist, basophils release histamine.

Correct Answer: C

Rationale: Hybridoma technology produces monoclonal antibodies; not fermentation or PCR .