In the blood attack foreign blood not compatible with the antigens on the blood.

Antibodies

The blood group antigen is found on the surface of erythrocytes, and it is being ignored y the immune system, but when antigen of another blood type is found it recognize it as a foreign and it is being attacked by the antibodies.

Antibodies are produced by the white blood cell of the body and act as a soldier for the body by the immune system. It recognizes and attacks foreign substances in the body.

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