Concept: It is the place where various immune cells and blood cells occur and develop, and is an important central immune organ of the body.

It is a hematopoietic organ; The birthplace of immune cells; It is also the only place where B cells differentiate, develop and mature.

It is the earliest organ to develop; Structure and size change with age

Function: 1. It is the place where T cells differentiate, develop and mature. 2. Immunomodulatory effect 3. Establish autoimmune tolerance and maintain immune homeostasis

Function: 1. It is the place where pluripotent hematopoietic stem cells proliferate and differentiate during the embryonic stage and has hematopoietic function. 2. It is the place where T cells and B cells settle. 3. Has the function of filtering blood 4. Participate in lymphocyte recycling

The largest peripheral immune organ in the body; Has blood storage function

Concept: Often located in superficial concave and hidden places of the human body, such as the neck, armpits, groin, etc. or near internal organs, arranged along blood vessels

Function: 1. It is a place where mature T lymphocytes and B lymphocytes settle 2. It is the place where the immune response occurs 3. Participate in lymphocyte recycling 4. The function of filtering lymph fluid

Lymph nodes are the most complete peripheral immune organs

B cell settlement site

Where T cells colonize

More B cells and plasma cells

More macrophages

Antigen receptor (TCR) is a unique marker of T cells; CD4 or CD8 molecules are only expressed on the surface of mature T cells, and their main function is to assist TCR in recognizing antigens; Costimulatory molecules are auxiliary molecules that provide secondary signals for T cell activation.

Antigen receptor (BCR) Costimulatory molecules are auxiliary molecules that provide second signals for parietal cell activation.

Including monocytes in blood and macrophages in tissues

Function: 1. Macrophage killing effect 2. Ingest, process, and present antigens 3. Immunomodulatory effect, through the secretion of a variety of cytokines for immune regulation 4. Anti-tumor effect

It is the APC with the strongest antigen-presenting ability.

Function: 1. Recognize, ingest and process antigens and participate in innate immunity 2. Antigen presentation and immune activation 3. Immunomodulatory effect 4. Induction and maintenance of immune tolerance

1. Interleukin (IL) 2. Interferon (IFN) 3. Tumor necrosis (TNF) 4. Colony stimulating factor (CSF) 5. Chemotactic cytokines 6. Growth factors (GF)

1. Acts in a non-specific manner and is not restricted by mh C 2. Efficiency of action 3. Network nature of function 4. Diversity of modes of action. CK can act locally through autocrine, that is, acting on its own production cells, and paracrine, that is, acting on nearby target cells.