Has no antigen in many textbooks it will state "no A-antigen and no B-antigen"(which imply the possibility of some other antigen) and some will even say, "no antigen" (which is true; antigens are things that attach to antigen binding sites, thus, if it does not fit any antigen binding sites, it is technically not a antigen but merely a "enzyme/protein") but this is just to reduce unnecessary and irrelevant information; they are only concerned about A-antibody, B-antibody, A-antigen, and B-antigen. Nonetheless, know that there are in fact antigens on o blood cells, they are just inactive. My guess is, N acetyl glactosamine on A antigen and Galactose on B antigens are Epitopes (: a small specific regions on antigens that are bound by the antigen receptors on lymphocytes and by secreted antib