Question

Which of the following T cell independent antigen acts through?

• A. T-cell
• B. B-cell
• C. Macrophages
• D. CD8+ T cells

Hint:

The label says no T cell help is needed, so they must trigger the antibody maker directly.

Answer 1

The Correct Option is B

Step 1: The name of the antigen group is itself the clue. If an antigen is labelled T cell independent, then by definition it does its work without leaning on T lymphocytes.

Step 2: So which cell does it engage instead? These antigens are usually big repetitive structures, like the polysaccharide coats and endotoxin of bacteria. Their repeating epitopes simultaneously clamp many B cell receptors on a single B cell, and that strong cross-linking is enough to switch the B cell on by itself. The pathway therefore runs through the B cell, which is option b.

Step 3: Since no helper T cell or antigen presenting cell processing is involved, the macrophage, the helper T cell and the cytotoxic CD8 T cell options are all off the mark. The antibody produced is largely IgM with weak memory.

Step 4: The direct line from repeating antigen to B cell receptor confirms the route.

\[\boxed{\text{B-cell}}\]