Question

Immunological features differentiating naïve B cells activated in primary immune responses from memory B cells functioning in secondary immune responses include the fact that [complete the sentence and assess each subsequent statement (1-7) as either factually correct (true) or incorrect (false)]:

8. the frequency of antigen-specific B cells is lower in secondary immune responses.

9. higher levels of IgM are produced in secondary immune responses.

10. the level of somatic hypermutation is higher in secondary immune responses.

11. B cells do not require T-cell help in secondary immune responses.

12. memory B cells express higher levels of MHC class II molecules.

13. naïve B cells express higher levels of co-stimulatory molecules.

14. the antibody produced is of higher affinity in secondary immune responses.

Answer 1

8.  False, There is high response against antigen in secondary immune response. There is high frequency of antigen-specific B cells in a secondary immune response.

9. False, In the primary response the major class of antibody produced is IgM whereas in the secondary response it is IgG or IgA or IgE.

10. True, the level of somatic hypermutation is higher in a secondary immune response. Because somatic mutation mechanism is activated after exposure to antigen.

11. False, Higher level of MHCII allows memory B cell to interact T cells more efficiently at lower doses.

12. True, memory B cells express higher levels of MHC class II molecules. Increased MHCII level facilitate antigen uptake and presentation.

13. False, memory B cells are known to express higher levels of co-stimulatory molecules.

14. True, The antibody produced is of higher affinity in a secondary immune response. This is known as affinity maturation