Control multiplication of helper, suppresser T-cell

Correct Answer: B

Rationale: Thymic factor controls helper and suppressor T-cell multiplication.

Correct Answer: C

Rationale: Cytokines from macrophages signal and coordinate immune responses ; they don't destroy pathogens directly , form vesicles , or primarily affect blood flow .

Correct Answer: C

Rationale: Co-stimulatory molecules (e.g., B7) bind CD28 on T cells for activation ; pattern recognition , DC activation , and killing are distinct.

Correct Answer: B

Rationale: CTLA-4 inhibits T-cell activation by competing with CD28 ; it doesn't activate (A, C) or target B7 directly .

Correct Answer: C

Rationale: Increased capillary permeability during inflammation allows fluid leakage, causing swelling ; bacteria , blood cells , and pus contribute but aren't the primary cause.