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
[{'content': 'CD4 is associated with HLA? \nSelect and explain. \nA. HLA 1, B. HLA 2, C. HLA 3, D. All of them', 'role': 'user'}, {'content': "Answer: B \nExplanation: 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).", 'role': 'assistant'}]