IMMUNOLOGY

Detailed explanation-1: -MHC molecules (also called the human leukocyte-associated [HLA] antigens) are cell surface glycoproteins that bind peptide fragments of proteins that either have been synthesized within the cell (class I MHC molecules) or that have been ingested by the cell and proteolytically processed (class II MHC molecules).

Detailed explanation-2: -An antigen that induces an immune response-i.e., stimulates the lymphocytes to produce antibody or to attack the antigen directly-is called an immunogen.

Detailed explanation-3: -Immunoglobulins (Ig) or antibodies are glycoproteins produced by plasma cells. B cells are instructed by specific immunogens, for example, bacterial proteins, to differentiate into plasma cells.

Detailed explanation-4: -Antigen: definition An antigen is any foreign substance that can elicit an immune response in the body (eg, antibody production) and is bound by the specific antibodies produced against it by the immune system. Antigens generally have high molecular weight and are commonly proteins or polysaccharides.

Detailed explanation-5: -An antigen is a foreign or “non-self” macromolecule that reacts with cells of the immune system. Not all antigens will provoke a response. For instance, individuals produce innumerable “self” antigens and are constantly exposed to harmless foreign antigens, such as food proteins, pollen, or dust components.

Detailed explanation-6: -Antigens are proteins that are found on the surface of the pathogen. Antigens are unique to that pathogen. The whooping cough bacterium, for example, will have different antigens on its surface from the TB bacterium. When an antigen enters the body, the immune system produces antibodies against it.