Spleen is a secondary lymphoid organ. Secondary lymphoid organs are those organs where B-cells and T-cells undergo proliferation and differentiation.
Spleen is a large bean-shaped organ which mainly contains lymphocytes and phagocytes.
Spleen is a large reservoir of erythrocytes.
Spleen acts as a filter of the blood by trapping blood-borne micro-organisms.
Red bone marrow and thymus are the primary lymphoid organs.