This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
CD4 is associated with HLA? 
Select and explain. 
A. HLA 1, B. HLA 2, C. HLA 3, D. All of them
B: HLA 2
Answer: B: HLA 2 
Explanation: Ans. is 'b' i.e., HLA 2 * MHC-II recognizes exogenous antigen (extracellular microbes, soluble proteins) and present it to CD4 helper T cells (MHC-II restricted).* MHC class I present antigen to cytotoxic CD-8 T cells (MHC-I restricted).