Answer: They remain in the body long-term and enable rapid, stronger response on re-exposure to the same antigen.
- A They attack and lyse pathogens directly on contact, without ever needing antigen recognition first
- B They remain in the body long-term and enable rapid, stronger response on re-exposure to the same antigen
- C They synthesize antibiotic-like compounds that directly and immediately kill invading bacteria
- D They respond in an identical, non-specific way to absolutely any antigen they ever encounter
Correct answer: B. They remain in the body long-term and enable rapid, stronger response on re-exposure to the same antigen
Explanation: Memory B and T cells are long-lived cells formed during the primary immune response. On re-exposure to the same antigen, they are quickly activated, dividing rapidly and producing a faster, larger secondary immune response.
An antibody is Y-shaped, with two identical antigen-binding sites at the tips of the variable regions - each shaped to recognise one specific antigen - while the constant (Fc) region at the base is recognised by immune cells to trigger further responses.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.