IMMUNOLOGY

Detailed explanation-1: -Human leukocyte antigens (HLA) are a group of identification molecules located on the surface of all cells in a combination that is almost unique for each person, thereby enabling the body to distinguish self from nonself.

Detailed explanation-2: -The antigens on your own cells are known as self-antigens, while those that do not originate in your body are called non-self antigens. Self-antigens are present on all your cells, but they’re particularly important in blood cells. You can only receive a blood transfusion from a donor with the same type of antigen.

Detailed explanation-3: -Antigens, small molecules, or peptides capable of eliciting an immune response are key elements in this process of distinguishing self from nonself. Antigens serve as labels that enable the immune system to distinguish between a normal interaction (self) and an encounter with a foreign threat (nonself).

Detailed explanation-4: -Antibodies are protective proteins produced by your immune system. They attach to antigens (foreign substances)-such as bacteria, fungi, viruses and toxins-and remove them from your body.

Detailed explanation-5: -Adaptative immunity somatically generates large repertories of receptors of T and B lymphocytes, [T Cell Receptor (TCR) and B Cell Receptor (BCR)], which may be able to virtually recognize any nonself antigen.

Detailed explanation-6: -Antigens are substances (usually proteins) on the surface of cells, viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can also be antigens. The immune system recognizes and destroys, or tries to destroy, substances that contain antigens.

Detailed explanation-7: -Any substance that is recognised as foreign and is capable of triggering an immune response is called an antigen (non self)