What are blood group antigens?
The surface of all cells, including red blood cells (RBC) that transport oxygen to cells in our body, has thousands of different proteins, carbohydrates and lipids (fats).The presence and the amount of each of these thousands of molecules is governed by the genes of a person.As the repository of genes in every human being is slightly different from those in others (except for identical twins), the surface of RBCs differs from person to person.Antigens can be imagined as portions of the thousands of molecules on the cell surface.RBCs from two persons will have some antigens that are the same and some that are different (present in one person but not the other). During development, the human immune system recognizes antigens of the body as ‘self’ and does not generate antibodies against them.However, it retains the potential to generate antibodies against billions of foreign antigens even though it has never encountered them. When a person’s system comes in contact with blood from anothe
