the antigens of the ABO blood group are located surrounded by the?

On the plasma membrane of the red blood cell (that's what the others said, and they're right).
There is also a gene that some people get that code for free A and B antigens in body fluids. These folks are called secretors, and the gene is dominant.
For example, I am a secretor. I own determined my blood type by adding antibodies to my saliva, as resourcefully as by traditional blood tests.
bed membrane of RBCs
on the red cell membrane
Karl Landsteiner observed ABO blood grouping in humans. The blood groups A, B, and AB are characterized by the presence of antigens on the surface of red blood cell.'O' blood is with out antigens on the surface of RBC. These are below the control of a gene located on chromosome nine in the human mortal.