Each of the following statements concerning class II MHC proteins is correct EXCEPT:
|A|| They are found on the surface of both B and T cells.|
|B|| They have a high degree of polymorphism.|
|C|| They are involved in the presentation of antigen by macrophages.|
|D||They have a binding site for CD4 proteins.|
a. The MHC class II are located on antigen presenting cells like macrophages, dendritic cells, monocytes, langerhans cells and B cells.
b. CD4 T lymphocytes recognizes peptide antigen only when it is presented by the antigen presenting cell in the peptide binding groove of MHC II molecules
c. MHC molecules are membrane-bound; recognition by T cells requires cell-cell contact. MHC Class II have a highly conserved α2 domain and a highly conserved β2 domain to which CD4 molecule of T helper cell binds.
d. In case of MHC Class II, there is a highly conserved region of α3 that binds the CD8 molecules present on CD8 T lymphocyte.
e. The antigen binding domains of class 1 and II molecules are highly polymorphic. Two individuals are highly unlikely to have the same MHC antigens. The MHC molecules of a particular individual, his or her haplotype, can be given a designation using tissue typing reagents.
f. The MHC genes are co-dominant, the products of both the parent alleles are expressed on the cell surface.