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
[{'content': 'Type of receptor present on T-cells are: \nSelect and explain. \nA. IgA, B. IgG, C. Prostaglandins, D. CD4', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Helper T cells\xa0\n\nCarries CD4 marker.\nHelps or induces immune responses.\nRecognize antigen in association with class II MHC.\nMacrophages are activated to kill intracellular microorganisms by secreting cytokines.\n\nParija SC. Textbook of Microbiology & Immunology. Elsevier Health Sciences; 2014. Page:127', 'role': 'assistant'}]