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: Pathology
[{'content': 'Most potent stimulator of Naive T-cells - \nSelect and explain. \nA. Mature dentritic cells, B. Follicular dentritic cells, C. Macrophages, D. B-cell', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mature Dendritic cells Mature B-cells and T-cells before antigenic exposure are called naive-B and T cells respectively. Sequence of events in activation of naive T cells. o Immature dendritic cells in the epidermis are called langerhans cell. o These immature dendritic cells (langerhans cells) capture the antigen in the epidermis. o After capturing the antigen these cells secrete cytokines. o These cytokines cause loss of adhesiveness of langerhans cells. o Langerhans cells separate from each other and migrate into lymphatic vessels. o In lymphatic vessel, maturation of langerhans cells takes place. Then these mature langerhans dendritic cells reach to naive T cells in the lymph nodes and present antigen to these cells and activate them.', 'role': 'assistant'}]