This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
CD4 lymphocytes (helper cells) recognize - 
Select and explain. 
A. HLA class I antigen, B. HLA class II antigen, C. HLA class III antigen, D. None of the above
B: HLA class II antigen
Answer: B: HLA class II antigen 
Explanation: Class II MHC antigens have single locus as HLA-D. - these antigens have fuher 3 loci: DR, DQ, and DP. Class II MHC is identified by B cells and CD4+ cells.( T helper cells). ReReference:arsh mohan textbook pathology, 7th edition, pg no:49 <\p>