This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2018, Subject name: Pathology
Naive T cell get activated by: 
Select and explain. 
A. NK cell, B. Dendritic cell, C. Macrophage, D. B-lymphocyte
B: Dendritic cell
Answer: B: Dendritic cell 
Explanation: Naive T cell get activated by antigen presenting cells such as Dendritic cell Macrophage B-lymphocyte Most impoant APC in activating naive T cell is dendritic cell Dendritic cell on skin is called as Langerhans's cell. They have granules called as Bier beck's granules These granules have rod like appearance with a dilated end hence known to have tennis racquet appearance Markers of Langerhans's cell CD 1 A S-100 HLA-DR Dendritic cell in lymph node is known as follicular dendritic cell. Follicular dendritic cell acts as a reservoir for HIV