Karl Landsteiner was born in Vienna on June 14, 1868. Landsteiner studied medicine
at the University of Vienna, graduating in 1891. Even while he was a student he had begun to do
biochemical research and in 1891 he published a paper on the influence of diet on the composition of
blood ash. In 1909, he classified the bloods of human beings into the now well-known A, B, AB, and O
groups and showed that transfusions between individuals of groups A to A or B to B do not result in
the destruction of new blood cells and that this catastrophe occurs only when a person is transfused
with the blood of a person belonging to a different group. Earlier, in 1901-1903, Landsteiner had
suggested that, because the characteristics, which determine the blood groups, are inherited; the blood
groups may be used to decide instances of doubtful paternity. In collaboration with Levine and Wiener,
this further work on the blood groups greatly extended the number of these groups, and in further
collaboration with Wiener they studied bleeding in the newborn children, leading to the discovery of
the Rh-factor in blood, which relates the human blood to the blood of the rhesus monkey.
ABO Blood Types
All humans and many other primates can be typed for the ABO blood group. There are four types: A, B, AB,
and O. There are two antigens and two antibodies that are mostly responsible for the ABO types. The specific
combination of these four components determines an individual's type. The table below shows the possible
permutations of antigens and antibodies with the corresponding ABO types ("yes" indicates the presence of a
component and "no" indicates its absence in the blood of an individual).
ABO
Blood Type
Antigen
A
Antigen
B
Antibody
anti-A
Antibody
Anti-B
A
yes
no
no
yes
B
no
yes
yes
no
O
no
no
yes
yes
AB
yes
yes
no
no
For instance, type A people will have the A antigen on the surface of their red cells (as shown in
the table below). As a result, anti-A antibodies will not be produced because they would cause
the destruction of their own blood. However, if B type blood is injected into their systems, antiB antibodies in their plasma will recognize it as alien and burst or agglutinate the introduced red
cells in order to cleanse the blood of alien protein.
ABO
Blood Type
Antigen
A
Antigen
B
Antibody
anti-A
Antibody
Anti-B
A
yes
no
no
yes
B
no
yes
yes
no
O
no
no
yes
yes
AB
yes
yes
no
no
Type O people do not produce ABO antigens.
Therefore, their blood normally will not be
rejected when it is given to others with different ABO types. As a result, type O people are
universal donors for transfusions. AB type people do not make any ABO antibodies. Their
blood does not discriminate against any other ABO type. Therefore, they are universal receivers
for transfusions.
ABO
Blood Type
Antigen
A
Antigen
B
Antibody
anti-A
Antibody
Anti-B
A
yes
no
no
yes
B
no
yes
yes
no
O
no
no
yes
yes
AB
yes
yes
no
no
It is easy and inexpensive to determine an individual's ABO type from a few drops of blood.
A
serum containing anti-A antibodies is mixed with some of the blood. Another serum with anti-B
antibodies is mixed with the remaining sample. Whether or not agglutination occurs in either
sample indicates the ABO type. It is a simple process of elimination of the possibilities. For
instance, if an individual's blood sample is agglutinated by the anti-A antibody, but not the antiB antibody, it means that the A antigen is present but not the B antigen. Therefore, the blood
type is A.
What's Your Type?
In some ways, every person's blood is the same. But, when analyzed under a microscope, distinct differences are
visible. In the early 20th century, an Austrian scientist named Karl Landsteiner classified blood according to those
differences. He was awarded the Nobel Prize for his achievements.
Landsteiner observed two distinct chemical molecules present on the surface of the red blood cells. He labeled one
molecule "A" and the other molecule "B." If the red blood cell had only "A" molecules on it, that blood was called
type A. If the red blood cell had only "B" molecules on it, that blood was called type B. If the red blood cell had a
mixture of both molecules, that blood was called type AB. If the red blood cell had neither molecule, that blood was
called type O.
If two different blood types are mixed together, the blood cells may begin to clump together in the blood vessels,
causing a potentially fatal situation. Therefore, it is important that blood types be matched before blood transfusions
take place. In an emergency, type O blood can be given because it most likely to be accepted by all blood types.
However, there is still a risk involved.
A person with type A blood can donate blood to a person with type A or type AB. A person with type B blood can
donate blood to a person with type B or type AB. A person with type AB blood can donate blood to a person with
type AB only. A person with type O blood can donate to anyone.
A person with type A blood can receive blood from a person with type A or type O. A person with type B blood can
receive blood from a person with type B or type O. A person with type AB blood can receive blood from anyone. A
person with type O blood can receive blood from a person with type O only.
Because of these patterns, a person with type O blood is said to be a universal donor. A person with type AB blood is
said to be a universal receiver. In general, however, it is still best to mix blood of matching types and Rh factors.
Are You Positive or Negative?
Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are certain
similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This
protein is also present in the blood of some people. Other people, however, do not have the protein. The presence of
the protein, or lack of it, is referred to as the Rh (for Rhesus) factor.
If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the
protein, your blood is said to be Rh negative (Rh-).
This Rh factor is connected to your blood type. For example, your blood may be AB+ which means that you have
type AB blood with a positive Rh factor. Or, you might have O- blood which means that you have type O blood with
a negative Rh factor.
It is particularly important for expectant mothers to know their blood's Rh factor. Occasionally, a baby will inherit an
Rh positive blood type from its father while the mother has an Rh negative blood type. The baby's life could be in
great danger if the mother's Rh negative blood attacks the baby's Rh positive blood. If this happens, an exchange
transfusion may save the baby's life. The baby's blood can be exchanged for new blood that matches the mother's.
http://www.biology.arizona.edu/human_bio/problem_sets/blood_types/markers.html (you can use a calculator to
predict child blood types)