The immune system includes all the organs, cells, and molecules whose function is to ensure the defense of the organism against pathogenic agents (bacteria, viruses, cancer cells, parasites, etc.). It has the ability to distinguish between self and non-self. It tolerates the organism’s cells that constitute the self and eliminates everything that is foreign to the organism (the non-self and altered self).
Immunity originally referred to an organism’s resistance to an infectious agent. This definition later expanded to include all reactions aimed at eliminating foreign substances. Immunity is the set of biological mechanisms that allow an organism to recognize and tolerate what belongs to it (self) and to recognize and reject what is foreign (non-self). The substances rejected include:
Foreign substances or infectious agents,
Altered self components (such as tumor cells and virus-infected cells)
- Enseignant: HANANE BOUKEMARA