IMMUNOLOGY
What is immunology ?
Immunology is the branch of biology that deals with the study of the immune system. Appearing very early during evolution, this system has evolved to distinguish self from nonself.
The body's defense reactions face pathogens such as:
- Viruses,
- Bacteria,
- Fungi, or protozoa.
This science has two aspects :
- Medical (autoimmune diseases, allergies, and graft rejection),
- Fundamental and mechanistic (mechanisms of antibody synthesis and maturation, complement system activation, mobilization and coordination of defense cells).
The collection of organs of the immune system is called the lymphoid system :
- Primary or central lymphoid organs (bone marrow, thymus),
- Secondary or peripheral lymphoid organs (lymph nodes, secondary lymphoid tissues, spleen),
- Tertiary lymphoid organs associated with mucosal surfaces (skin, respiratory system, digestive tract, genital tract, etc.).
The different types of immune reactions are :
- Humoral immunity (antibodies),
- Cellular immunity (NK lymphocytes, granulocytes, macrophages, dendritic cells, CD8+ T lymphocytes, CD4+ T lymphocytes).
