EXERCISE №11 – IMMUNOGENETICS OF THE BLOOD GROUPS. ALLOANTIGENS ON HUMAN ERYTHROCYTES

What are blood group antigens categorized as?

Alloantigens, as they trigger an immune response in other individuals of the same species.

Who discovered the A and B antigens, and in what year?

Karl Landsteiner in 1901.

What is the primary antibody type present in the plasma of ABO blood groups?

IgM.

Define 'Multiple allelism' in the context of the ABO blood group system.

The I gene on chromosome 9 has three alleles: I^A, I^B, and I^O.

What is the genotype for blood type A?

I^A I^A or I^A I^O.

What does the H gene on chromosome 19 produce?

Fucosyltransferase 1 (FUT1), which adds fucose to form H antigen.

What is the result of the hh genotype in the Bombay phenotype?

No H antigen is formed, rendering the individual unable to produce A or B antigens.

What is the purpose of the Se gene in relation to blood group antigens?

It determines the ability to secrete ABO antigens into body fluids.

What happens during the primary sensitization in Rh incompatibility?

Fetal Rh+ RBCs enter the mother's blood, causing her to produce IgM and B memory cells.

What are the key antibodies for the ABO(H) blood group system?

Anti-A and Anti-B antibodies.

Explain why O is considered the universal donor blood type.

Blood type O has no A or B antigens, so it cannot be agglutinated by anti-A or anti-B antibodies.

What does the term 'agglutination' imply in blood typing tests?

It indicates that an antigen (from the blood sample) is present that reacts with a specific antibody.

What is the consequence of an Rh– individual receiving Rh+ blood?

They will produce anti-D antibodies, leading to severe reactions in future transfusions.

List the blood types that the universal recipient (AB) can receive from.

A, B, AB, O.

What are some applications of blood group typing?

Blood transfusions, organ transplants, and paternity testing.

What key antigen is associated with the Rhesus blood group system?

The D antigen.

What is the genetic basis of the Lewis blood group system?

It is determined by alleles Le and le located on chromosome 19.

What might indicate a person is Duffy-negative?

They lack the Duffy antigen, leading to resistance to malaria caused by Plasmodium vivax.

What does RhoGAM do in pregnancy?

It prevents the mother from developing antibodies against Rh+ cells from the fetus, protecting subsequent pregnancies.

How does the Bombay phenotype affect blood transfusion eligibility?

People with hh genotype can only receive blood from other Bombay donors, and have anti-A, anti-B, and anti-H antibodies.

What type of antibodies are associated with Rh incompatibility?

Anti-D antibodies which are typically immune (IgG) and develop after a Rh+ blood exposure.

How is the synthesis of A and B blood group antigens achieved?

Through the action of specific glycosyltransferases, which add different sugars to the H antigen.