BIOLOGY 3 Lecture Notes - Lecture 24: Human Leukocyte Antigen, East Los Angeles College, Aplastic Anemia
Document Summary
The human leukocyte antigen (hla) system or complex is a gene complex encoding the major histocompatibility complex (mhc) proteins in humans. These cell-surface proteins are responsible for the regulation of the immune system in humans. The hla gene complex resides on a 3 mbp stretch within chromosome. Hla genes are highly polymorphic, which means that they have many different alleles, allowing them to fine-tune the adaptive immune system. The proteins encoded by certain genes are also known as antigens, as a result of their historic discovery as factors in organ transplants. To minimize rejection the donor and recipient should have nearly identical gene variants for human leukocyte antigen (hla) complex. 1:4 chance of an identical match among siblings. Certain allele combinations are more common in specific ethnic groups than in others. There are 309 known alleles of hla-a, 167 of hla-c, and 563 different alleles of hla-d.
