This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Human Immunodeficiency Virus, Subject name: Microbiology
AIDS involves: 
Select and explain. 
A. T - helper cells, B. T - suppressor cells, C. T - cytotoxic, D. B. cells
A: T - helper cells
Answer: A: T - helper cells 
Explanation: Ans. is 'a' i.e., Helper T Cells (Ref: Ananthanarayan, 9th/e, p. 574, and 8th/e, p. 572)The receptor for the virus is the CD4 antigen on surface. The cells affected are:- CD4 T Cells (major target).- B lymphocytes.- Monocytes and macrophages.- Langerhans cells in dermis.- Glial cells and microglia in the CNS.- Follicular dendritic cells from tonsils can be infected by HIV without the involvement of CD4.