Basic components of the immune system part 28

MHC class II antigens also exhibit a similar structure with the groove being formed by the α1 and β1 chains. Unlike class I antigens present on most nucleated cells, the class II antigens are restricted to a few types: macrophages, B cells,and activated T cells. In humans, there are three groups of class II antigens: namely, HLA-DP, HLA-DQ and HLA-DR