After maturation, lymphocytes migrate to certain organs which provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells. Identify the organ that performs this function from the given options.

Step-by-step solution

Primary lymphoid organs (bone marrow and thymus) are the sites where immature lymphocytes differentiate into antigen-sensitive lymphocytes. After maturation, lymphocytes migrate to secondary lymphoid organs, which provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells. Spleen is a secondary lymphoid organ. Thymus and bone marrow are primary lymphoid organs, while the thyroid is an endocrine gland. Answer: Spleen