L'immunologie est la branche de la biologie qui s'occupe de l'étude du système immunitaire. Apparu très tôt au cours de l'évolution, ce système a évolué pour distinguer le non-soi du soi.
Les réactions de défense de l'organisme font face aux organismes pathogènes :
- Virus.
- Bactéries.
- Champignons ou protozoaires.
This science has 2 aspects :
- The medical aspect (Autoimmune diseases, allergies and transplant rejection).
- The fundamental and mechanistic aspect (The mechanisms of synthesis and maturation of antibodies, activation of the complement system, mobilization and coordination of defense cells).
The set of organs of the immune system is called the lymphoid system :
- 1- Primary or central lymphoid organs (bone marrow, thymus).
- 2- Secondary or peripheral lymphoid organs (Lymph nodes, Secondary appendages, Spleen).
- 3- Tertiary lymphoid organs associated with mucous membranes (skin, respiratory system, digestive tract, genital tract...)
The different types of immune reactions are :
- 1- Humoral immunity (antibodies).
- 2- Cellular immunity (NK lymphocytes, granulocytes, macrophages, dendritic cells, TCD8+ lymphocytes, TCD4+ lymphocytes).
