Methods And Contributions Of The ABO Antigen - 1713 Words

Another group of antigens that is of much less importance than the HLA antigens is the ABO antigens. This is because, in mixed leukocyte cultures, ABO incompatibility does not cause stimulation. However, they are still important since ABO incompatibility can cause acute rejection of grafts with primary blood supply such as the kidney and the heart. This is mainly due to the high degree of expression ABO blood group antigens in internal organs. Secondly, antibodies to the blood group antigens are present and pre-formed in mismatched recipients. However, there have been advances in medicine that have prevented rejection of the grafts by suppressing the immune system. These have made it possible for organ transplants to be performed across†¦show more content†¦The serum is tested for the possible presence of antibodies to either the ABO antigens or the HLA antigens. The presence of antibodies has been known to cause hyperacute renal graft rejection. As such, a positive serologi c crossmatch contraindicates renal transplantation (Chinen Buckley 2012). However, there are strategies being used in case the mismatch is unavoidable. This includes techniques such as plasmapheresis. The degree of HLA matching is directly related to the possibility of long-term survival. Mechanisms of Graft Rejection Both cellular and humoral immunity is involved in the response to the graft. The main cells involved in the rejection of grafts are the T cells. First, the hosts’ CD4 and CD8 T cells recognize antigens on the donor cells through their T-cell receptors. The T-cell receptor interacts with the antigens presented by the MHC molecules and the interaction between the ligand and receptor on the surface of the T-cell lead to the recognition of an antigen. There are a number of factors such as peripheral tolerance which ensure that these complexes are not recognized by the immune system of the host. As a result, the host does not have an autoimmune reaction. Alternatively, the T cells of the host may identify the MHC molecules of the graft on the graft or donor organ cell. The MHC molecule and allo-peptide appear similar in shape to the molecules and peptides of the donor by the host T cells. As a result, the tissue of the donor is recognizedShow MoreRelatedGenetic Variation Between Human Populations3106 Words   |  13 Pagesselection are distinctive because they reflect uncommon patterns of allele frequencies at a particular locus when compared to the underlying genetic variation. Candidate based gene approaches, Genome wide association studies (GWAS), haplotype based methods and various statistical tests such as Tajima’s D statistic are used to detect these signatures of selection within the human genome. This essay uses specific examples to discuss the evidence of infectious agents influencing genetic variation in theRead MoreHow Technology Has Impacted Criminal Investigation Essay2211 Words   |  9 Pagesone science that i s most commonly used in everyday life. It is also a branch of science that incorporates other branches of science such as biology, chemistry, and etc. Since it is used almost every day â€Å"No one can dispute the importance of the contributions to society made by forensic science; the ability to solve crime is undeniably important† (Hunter 13). Forensic science has given criminal investigation a new edge. â€Å"Advances in science have opened the door for more effective evidence discovery