CD4 lymphocytes (helper cells) recognize -: (A) HLA class I antigen, (B) HLA class II antigen, (C) HLA class III antigen, (D) None of the above
Answer is B. 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>