Question: 156. After maturation, in primary lymphoid organs, the lymphocytes migrate for interaction with antigens to secondary lymphoid organ(s)/tissue(s) like:
A. thymus
B. bone marrow
C. spleen
D. lymph nodes
E. Peyer’s patches
Choose the correct answer from the options given below:
(1) B, C, D only
(2) A, B, C only
(3) E, A, B only
(4) C, D, E only
Answer: Option (4)
Explanation:
Primary lymphoid organs include thymus and bone marrow. These are the sites where lymphocytes mature but do not interact with antigens.
After maturation, lymphocytes migrate to secondary lymphoid organs where they encounter antigens and initiate immune responses.
Secondary lymphoid organs/tissues include:
• Spleen → filters blood and exposes lymphocytes to blood-borne antigens.
• Lymph nodes → filter lymph and present antigens to lymphocytes.
• Peyer’s patches (in small intestine) → lymphoid tissues involved in gut immunity.
Thymus and bone marrow (A and B) are primary lymphoid organs, so they are not included.
Thus, correct secondary lymphoid organs from the list are C, D, and E.