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
Most potent stimulator of naive Tcells? 
Select and explain. 
A. Mature dendritic cells, B. Follicular dendritic cells, C. Macrophages, D. B cell
A: Mature dendritic cells
Answer: A: Mature dendritic cells 
Explanation: Ans. is 'a' i.e., 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 : . Immature dendritic cells in the epidermis are called langerhans cells. . These immature dendritic cells ( langerhans cells) capture the antigen in the epidermis. . After capturing the antigen, these cells secrete cytokines. . These cytokines cause loss of adhesiveness of langerhans cells. . Langerhans cells separate from each other and migrate to lymphatic vessels. . In lymphatic vessel, maturation of langerhans cells takes place. . Then these mature langerhan dendritic cells reach to naive T cells in the lymph nodes and present antigen to these cells and activate them.