This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
CD4 is marker of 
Select and explain. 
A. Monocyte, B. Tcell, C. Bcell, D. None
B: Tcell
Answer: B: Tcell 
Explanation: Ref Robbins 7/e p670;9/e p191 There are 4 main types of T cells. CD4+ Helper Cells. CD4+ helper cells help in the maturation of B cells into plasma cells and memory B cells. ... CD8+ Cytotoxic Cells. CD8+ cytotoxic cells cause lysis of virus-infected and tumour cells. ... Memory T Cells. ... Natural Killer T Cells.