HLA D antigens are proteins found on the surface of immune cells. The spelling of this word can be broken down using the International Phonetic Alphabet (IPA) transcription. H is pronounced as /eɪtʃ/, L as /ɛl/, and A as /eɪ/. The letter D is pronounced as /di/, while the word 'antigens' is pronounced as /ænˈtaɪdʒənz/. The HLA D antigens are used to determine tissue compatibility for transplantation and play a vital role in the body's immune response. Understanding the correct spelling and pronunciation of this term is necessary in the field of immunology.
HLA D antigens, also known as human leukocyte antigen D antigens, are proteins found on the surface of cells in the immune system that play a crucial role in immunological responses. They are a subset of HLA proteins, which are encoded by the major histocompatibility complex (MHC) genes located on chromosome 6 in humans.
HLA D antigens are primarily concerned with presenting foreign antigens to specialized immune cells called T lymphocytes. These antigens are presented on the surface of antigen-presenting cells, such as macrophages, dendritic cells, and B cells. When a pathogen or foreign substance enters the body, it is processed by these antigen-presenting cells and then presented to specific T cells.
HLA D antigens are classified into two groups: HLA-DR and HLA-DQ. HLA-DR antigens are responsible for presenting antigens to helper T cells, which then stimulate immune responses against the foreign substance. HLA-DQ antigens, on the other hand, present antigens to both helper T cells and cytotoxic T cells, aiding in the activation of the immune system against infected or cancerous cells.
These HLA D antigens are highly polymorphic, meaning they have multiple variations within the population. This diversity allows individuals to respond to a wide range of pathogens, as not all antigens can be presented by every HLA D variant. Incompatibility or mismatch between the HLA D antigens of organ donors and recipients is a significant consideration in transplantation procedures, as it can result in rejection of the transplanted organ.