Tissue antigens

An antigen present only in some individuals of a species and capable of inducing the production of an alloantibody by individuals which lack it.
Graft antigen- Present on the grafted Tissue/organs.
Foreign antigens ( blood , tissue)
Other alloantigens : Human ABO blood group antigens and Some tissue specific antigens
Obviously, in the case of tissues that lack alloantigens, such as cartilage or heart valves, there is no immunologic barrier to transplantation.
Cytokines produced by host T-cells activated in response to alloantigens play a major role in graft rejection.
All allografts between individuals with identical HLA haplotypes will be accepted.

1. Amjad Khan Afridi Chapter # 08 Tissue Antigens

2. Alloantigens An antigen present only in some individuals of a species and capable of inducing the production of an alloantibody by individuals which lack it. Graft antigen- Present on the grafted Tissue/organs. Foreign antigens ( blood , tissue) Other alloantigens : Human ABO blood group antigens and Some tissue specific antigens Obviously, in the case of tissues that lack alloantigens , such as cartilage or heart valves, there is no immunologic barrier to transplantation. Cytokines produced by host T-cells activated in response to alloantigens play a major role in graft rejection. All allografts between individuals with identical HLA haplotypes will be accepted.

3. Types of Alloantigen 1. Antigens of Red Blood Cell Present on the surface of RBC ABO system (blood typing)- very important in transfusion Rh system 2. HLA system (Human leukocyte antigen) - relate to transplantation - very important in immune regulation - Which cells belong in your body & which do not.

4. The ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes (RBC). In human blood transfusions it is the most important of the 36 different blood type (or group) classification systems currently recognized Most immunogenic

5. Genetics A and B are  codominant , giving the AB phenotype. Blood groups are inherited from both parents. The ABO blood type is controlled by a single gene (the ABO gene) with three types of  alleles  :  i ,  I A , and  I B .

6. A person with A+ blood receives B+ blood. The B antibodies in the A+ blood attack the foreign red blood cells by binding to them. The B antibodies in the A+ blood bind the antigens in the B+ blood and agglutination occurs. This is dangerous because the agglutinated red blood cells break after a while and their contents leak out and become toxic

7. Transfusion if a person who is going to receive blood has antibodies matching the donor blood's antigens, the red blood cells in the donated blood will clump. People with blood group O Rh - are called "universal donors" and people with blood group AB Rh+ are called "universal receivers."

8. Rh blood group system It is the second most important blood group system, after the ABO system. The Rh blood group system consists of 49 defined blood group antigens five antigens D, C, c, E, and e are the most important.

9. Rh Factor The D antigen is the most immunogenic of all the non-ABO antigens The terms  Rh factor ,  Rh positive , and  Rh negative  refer to the  Rh(D) antigen  only. 

10. Erythroblastosis fetalis . known as hemolytic disease of the newborn. caused by transplacental transmission of maternal antibodies to fetal RBCs Rh incompatibility happens during pregnancy if mother's blood is Rh- and the baby's is Rh+

11. Heterophile Ag ( forssman Ag) common Ags shared by different species- no specificity of species-