Wondershare EdrawMind
マインドマップギャラリー antigen
- 46
antigen
Mind map of antigens. Antigens refer to the highly specificity of antigens that selectively stimulate adaptive immune cells to produce immune responses and their interaction with immune response products.
2023-10-17 20:58:02 に編集されました
- おすすめ
- アウトライン
antigen
Basic features
Immunogenicity
immunoreactivity
Complete antigen: a substance that is both immunogenic and immunoreactive Such as animal serum and pathogenic microorganisms (most of them in nature)
Hapten (incomplete antigen): a substance that is only immunoreactive but not immunogenic Simple small molecule substances such as certain polysaccharides and drugs
When hapten acts on the body alone, it has no immunity. When combined with carriers such as macromolecular proteins in the body, Can acquire immunogenicity and become a complete antigen
Antigen specificity
🈯️Antigen selectively stimulates adaptive immune cells to produce immune responses and their Highly specific interaction with immune response products
Antigenic determinants are also called antigenic epitopes
Antigenic epitope
Classification of antigenic epitopes
Sequential and conformational epitopes
Sequential epitope: mainly recognized by TCR on the surface of T cells, but also recognized by BCR on the surface of B cells
Conformational epitopes: recognized by BCRs and antibodies on the surface of B cells
T cell epitopes and B cell epitopes
T cell epitope: an epitope recognized by TCR on the surface of T cells, located at any part of the antigen molecule. After processing by antigen-presenting cells, it is expressed on the antigen in the form of an antigen peptide-MHC molecule complex. Presented on cell surface for recognition by T cells
B cell epitope: an epitope recognized by BCR and specific antibody molecules on the surface of B cells, usually located on the surface of antigen molecules Can be directly recognized by BCR without processing
Common epitopes and cross-reactivity
Factors affecting antigen immunogenicity
foreignness of antigen
Generally speaking, the farther the genetic relationship between the antigen and the body, the greater the difference in tissue structure, the stronger the foreign body, the more emphasis the antigen has on the body's immunogenicity.
In vitro: such as various pathogens, animal proteins and allografts
In the body: some self-materials whose structure has been changed due to physical, chemical and biological factors and normal self-materials that have not been in contact or fully contacted with immune cells during the embryonic period Such as eye lens protein, brain tissue and sperm
Physicochemical properties of antigen molecules
Chemical properties: Proteins, glycoproteins and lipoproteins are highly immunogenic. Polysaccharides and polypeptides have certain immunogenicity, Lipids and nucleic acids are less immunogenic
molecular weight
The larger the molecular weight, the more antigen epitopes it contains, and the stronger the immunogenicity.
Chemical composition and structure
It is composed of linear amino acids and is easily degraded in the body, so it has weak immunogenicity. Contains aromatic amino acids and has strong immunogenicity
accessibility
The degree to which the antigenic epitope in the antigen molecule is accessible to the BCR
physical state
The immunogenicity of the polymerized state is significantly enhanced compared to its monomer. Immunogenicity of particulate antigens > Immunogenicity of soluble antigens
body factors
genetic factors
Age, gender, health status and stress
The immune response ability of individuals to antigens in young adults is stronger than that in children and older adults
How antigens enter the body
Immune route effect: intradermal > subcutaneous > intraperitoneal vein > oral
Type of antigen
Classification based on whether T cells are required to participate in antigen-induced antibody production
Thymus-dependent antigen (majority)
Antigens that stimulate the differentiation of B cells into plasma cells to produce antibodies that require the assistance of Th cells are also called T cell-dependent antigens, or TD antigens for short.
Thymus-independent antigen (minority)
Antigens that stimulate B cells to differentiate into plasma cells to produce antibodies without the assistance of Th cells, also known as T cell-independent antigens, or TI antigens for short
Classification based on the relationship between the antigen and the body
xenoantigen
Pathogenic microorganisms
Exotoxins
It is a toxic protein secreted outside the bacteria by certain bacteria during their growth and metabolism. It has strong immunogenicity and can stimulate the body to produce specific antibodies, that is, antitoxins
toxoid
It is the loss of toxic effect of bacterial exotoxins obtained after treatment with formaldehyde aq. Biological agents that retain their original immunogenicity. Such as tetanus toxoid and diphtheria toxoid
Antitoxin
Derived from animal immune serum. For humans, it is a heterogeneous antigen that can stimulate the body to produce antibodies against animal serum. Repeated use can induce hypersensitivity reactions in the body. Therefore, skin allergy testing must be done before clinical use of such biological agents.
alloantigen
ABO blood group antigen
RH blood group antigen
Human Leukocyte Antigen (HLA)
autoantigen
Cryptoantigens: eye lens proteins, sperm and brain tissue
Altered/modified autoantigens: refers to the changes in pathogenic microbial infections and certain physical (such as radiation) and Autoantigens formed by changes in the structure of one's own tissues to produce new epitopes under the influence of chemical (such as drugs) factors
heterophile antigen
Forssman antigens and species are common antigens between humans, animals, and plant organisms.
Classification based on whether the antigen is synthesized in antigen-presenting cells
Endogenous antigen: an antigenic substance that is newly synthesized in antigen-presenting cells and exists in the cytoplasm.
Exogenous antigens: Antigen-promoting cells take in intracellular antigenic substances from the outside through phagocytosis, phagocytosis, etc.
Superantigens, mitogens and adjuvants
superantigen
The superantigens of d阝T cells include Staphylococcus aureus enterotoxin, group A hemolytic streptococcus pyrogenic exotoxin, and mouse mammary tumor virus protein.
mitogen
T cell mitogen
Phytohemagglutinin, concanavalin A, pokeweed mitogen
B cell mitogen
pokeweed mitogen, staphylococcal protein A
Adjuvant
biological adjuvants
Inorganic compound adjuvant
synthetic adjuvants
Adjuvants used in animal experiments
Freund's complete adjuvant
Freund's incomplete adjuvant