As I just mentioned, blood transfusion
is the most common type of transplant.
And here we can see the way in which the blood group
antigens are inherited looking at the ABO blood groups.
So here we have a father who is blood
group A and a mother who is blood group B.
The first child inherits the null allele from the father
and from the mother, and therefore is blood group O.
And they will produce natural antibodies
against both blood group A and blood
group B, because those are not antigens
which are part of their body makeup.
They will not be immunologically
tolerant to those antigens.
And structures that are very similar to those
particular antigens are present on many common microbes.
So we produce lots of natural antibodies against the
A and B antigens if we lack those antigens ourselves.
And this individual being blood
group O will be a universal donor.
Their second child has inherited the A blood group
from the father and the null allele from the mother.
And will be blood group A, and will
produce B blood group specific antibodies.
The third child is blood group B, having
inherited B from the mother and the
null allele from the father, and produces
blood group A antibodies from birth.
And then child four is AB blood group.
And because both the A blood group and the B blood group
are now self antigens for this individual, they do not
produce antibodies against either blood group A or blood
group B antigens, and will be a universal recipient.