Which of the following is NOT a function of the spleen?

The spleen performs several essential functions in the immune system and hematologic processes. Among these is its role in the production of lymphocytes, which are white blood cells crucial for immune responses. Additionally, the spleen acts as a reservoir for blood, storing red blood cells and platelets, and can release them into circulation as needed, particularly in response to hemorrhage.

One notable function of the spleen is the formation of antibodies through its lymphoid tissue. The spleen processes blood, filtering out old and damaged cells, and engages with antigens to kickstart an immune response, including antibody production.

However, the filtration of lymph fluid is primarily performed by the lymphatic system, particularly through lymph nodes, rather than by the spleen. The spleen filters blood, but not lymph fluid; thus, it does not play a direct role in lymph filtration. This distinction clarifies why the filtration of lymph fluid is not a function of the spleen, making it the correct choice in this context.