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
Interferon gamma, which is known to enhance the cytotoxic effects of macrophages are secreted by which of the following components of the immune system? 
Select and explain. 
A. CD4 T cell, B. CD8 cells, C. RBC, D. Neutrophils
A: CD4 T cell
Answer: A: CD4 T cell 
Explanation: CD4+ Thl T cells secrete interferon gamma, a cytokine that enhances the cytotoxic potential of activated macrophages. These activated macrophages show increased phagocytic and respiratory activity, along with enhanced antigen presenting capacity.