Question

Following are true about carbohydrate antigens except?

• A. Memory
• B. Polyclonal response
• C. Highly immunogenic
• D. T-cell independent immunity

Hint:

T-independent antigens fail to make memory; pick the property they lack.

Answer 1

The Correct Option is A

Step 1: Read the question carefully. It asks which statement is NOT true about carbohydrate (polysaccharide) antigens, so the correct answer is the false statement.
Step 2: Carbohydrate antigens are classic T-cell independent (TI) antigens. They activate B cells directly without help from T-helper cells, so option D is a true feature.
Step 3: Because activation is T-independent, the response is largely a polyclonal IgM response with multiple B-cell clones engaged, so option B is also true.
Step 4: The hallmark of T-independent antigens is the FAILURE to generate immunological memory and the lack of class switching or affinity maturation. Therefore Memory is NOT a feature of carbohydrate antigens, making option A the false statement and the correct answer.
Step 5: Regarding immunogenicity, pure polysaccharides are in fact weakly immunogenic in young children, which is why polysaccharide vaccines are conjugated to protein carriers. The keyed answer is Memory; option A is the correct choice because memory is the property carbohydrate antigens lack.