Red blood cells (erythrocytes). Blood groups
The membrane of the red cell has on its surface a group
of molecules that confer blood groupspecificity (i.e.,
that differentiate blood cells into groups). Most blood
group substances are composed of carbohydrate linked
to protein, and it is usually the chemical structure
of the carbohydrate portion that determines the specific
blood type. Blood group substances are antigens capable
of inducing the production of antibodies when injected
into persons or animals lacking the antigen. Detection
and recognition of the blood group antigens are accomplished
by the use of serum containing these antibodies. The
large number of different red cell antigens makes it
extremely unlikely that persons other than identical
twins will havethe same array of blood group substances.
(For a full treatment of the subject, see blood groups.)
