The body's natural defense function formed during the long-term germline evolution process

Heritable, no antigen stimulation required, not specific

A targeted process acquired by the body after contact with antigenic substances

Not hereditary, requires antigen stimulation, strong specificity

An immune organ that produces immune cells and induces their differentiation and maturation

Lymphoid stem cells develop into precursor cells of various lymphocytes

The site where all immune cells are produced

Site of immune cell differentiation and maturation (except T cells)

The earliest lymphocytes that occur during the embryonic stage. The thymus is relatively large in newborn animals. Produces thymosin to promote T cell maturation.

Site of T cell differentiation and maturation

The location of multifunctional hematopoietic stem cells

The lymphoid organ unique to birds is also called the supracoelal bursa. The size of chicks is largest when they are 3-4 months old, and gradually degenerates and shrinks after sexual maturity. Produce cystokinin, which promotes B cell maturation.

Has the function of a peripheral immune organ

structure

Immune Function

Immune Function

digestive tract submucosal lymphoid tissue

Lymphoid tissue under respiratory tract mucosa

Breast glands, lacrimal glands, salivary glands

Glands in the eye sockets of birds. Local immunity and regulation of humoral immunity, and can also secrete tears to play a non-specific protective role.

It has specific antigen receptors, which can activate, proliferate and differentiate after being stimulated by antigens, and produce specific immune responses.

Able to capture and process antigens and present them to T lymphocytes

Membrane molecules that exist on the surface of immune cells and are related to the differentiation and development of immune cells.

Membrane molecules that mediate contact and binding between cells or between cells and matrix

T cell antigen receptor TCR

E receptor

Cytotoxic T cells

Helper T cells

Regulatory/inhibitory T cells

memory T cells

B1-T cell independence only produces IgM, does not show re-response, and easily forms tolerance.

B2-T cell dependent can produce IgM and IgG

Antigen receptor BCR

complement C3b receptor

Receptor FcR

mitogen receptor

Cytokine receptor

Epstein-Barr virus receptor

Monocytes enter the tissue and become macrophages

effect

Humoral immunity, antigen presentation

neutrophils

eosinophils

basophils

platelets

red blood cells

Substance type

molecular size

chemical components

Epitope accessibility

Physical properties

Foreign body property

Ways of entry into the body

body genetic factors

Antigenic determinant (epitope)

ABO blood type

bacteria

Virus

It is a "Y" shaped molecule composed of four peptide chains, two identical heavy chains and two identical light chains.

The heavy chain consists of 420-446 amino acid residues and has a molecular weight of 50-75kDa. According to the different heavy chains, immunoglobulins can be divided into 5 categories: IgG, IgM, IgA, IgD, and IgE. Each type of Ig can also be divided into subcategories based on the composition of the amino acid residues in its hinge region and the number and position of disulfide bonds.

Light chain L

Heavy chainH

Variable region V

constant region C

Hypervariable region HV

skeleton area FR

Hinge region: There are 10-60 amino acids between CH1 and CH2, rich in proline and disulfide bonds, difficult to form α-helices, and very sensitive to protease treatment. Open and close freely and can be expanded to 180 degrees.

Suitable for binding to antigen-binding sites and antigenic determinants at different distances

Exposing the complement binding site creates conditions for complement activation.

The polypeptide chain molecules of immunoglobulins can fold to form several ring-shaped globular structures connected by intra-chain disulfide bonds. These globular structures are called functional domains of immunoglobulins.

J chain is also called the connecting chain: it refers to a short stretch of cysteine-rich polypeptide that connects two immunoglobulin monomer molecules. Unique to individual immunoglobulins.

Function: Fab—retains the function of specifically binding to antigen, but unit price Fc—retains the antigenicity of the heavy chain and the corresponding functional region biological activity

Function: F(ab’)2—has the function of specifically binding to antigen and is bivalent. pFc’—small molecule polypeptide fragment without any biological activity