Blood Transfusion

00:01 As I just mentioned, blood transfusion is the most common type of transplant.

00:05 And here we can see the way in which the blood group antigens are inherited looking at the ABO blood groups.

00:15 So here we have a father who is blood group A and a mother who is blood group B.

00:21 The first child inherits the null allele from the father and from the mother, and therefore is blood group O.

00:31 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.

00:42 They will not be immunologically tolerant to those antigens.

00:46 And structures that are very similar to those particular antigens are present on many common microbes.

00:52 So we produce lots of natural antibodies against the A and B antigens if we lack those antigens ourselves.

01:01 And this individual being blood group O will be a universal donor.

01:08 Their second child has inherited the A blood group from the father and the null allele from the mother.

01:17 And will be blood group A, and will produce B blood group specific antibodies.

01:25 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.

01:38 And then child four is AB blood group.

01:43 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.