This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
CD4 cells are involved in all of the following processes, EXCEPT: 
Select and explain. 
A. Acting as a helper function for B cells, B. Processing and presenting antigens, C. Producing and releasing interleukin-2, D. Producing and releasing interferon-gamma
B: Processing and presenting antigens
Answer: B: Processing and presenting antigens 
Explanation: CD4 cells or T cells, have all of the functions listed except for processing and presenting antigens. Ref: Kuby Immunology, 6th Edition, Page 209