What are the types of antigens in the novel coronavirus antigen detection kit?
Definition of antigen：
It is a substance that can combine with TCR of T and BCR (lymphocyte antigen receptor) of B, promote their proliferation and differentiation, produce antibodies or sensitized cells, and combine with them to exert immune effects.
Two characteristics of antigen：
Immunogenicity
The ability of antigen to stimulate the body to produce immune response, induce antibodies or sensitize lymphocytes.
Able to stimulate response
antigenicity：
Antigen has specific binding ability with the its induced antibody or sensitized lymphocyte
The product (antibody, etc.) after the stimulation reaction can specifically bind to itself
The classification guided by this: immunogen = complete antigen, incomplete antigen (only antigenicity) = hapten
Factors influencing immunogenicity
A.Contribution of the antigen
The following are all positively related
1.Size
2.Chemical complexity
3.Chemical composition
4.Conformation and accessibility
5.Physical form
B.Contribution of the interaction between host and antigen
Specificity:
Specificity refers to the specificity that the antigen stimulates the body to produce an immune response and the reaction of its response products = a specific antigen can only stimulate the body to produce specific antibodies or sensitized lymphocytes, and can only specifically bind to the antibody or lymphocytes that respond to the antibody.
the types of epitope
conformational epitope& sequential epitope
TCR & BCR
TD Ag (thymus dependent antigen): this kind of antigen stimulates B to produce antibodies that depend on t help, also known as T cell dependent antigen. [most human proteins are]
Ti Ag (thymus independent antigen): this kind of antigen stimulates B to produce antibodies independent of t help, also known as T cell dependent antigen.
Compared with the two, TD AG is more versatile:
Nonspecific immunostimulators:
Not typical but awesome
Superantigens are generally:
Extracellular toxin, retroviral protein
TCR binding site V β \ beta β
Direct stimulation of T cells
The reactive cells were CD4 + T cells
MHC binding site: non polypeptide region
Mitogen
Also known as mitogen, it can cause cells to undergo mitosis and then proliferate.
It is an important mitogen that acts on T and B cells of human and mouse.
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