Host Antiviral Immunity

The basic law of antiviral immunity is basically the same as other microbial immune mechanisms, including natural non-specific immunity and acquired sexual immunity. But in the body of these two aspects can not be divided, both the common coordination role, but also the characteristics of anti-virus immune itself.

First, non-specific immunity

(I) Interferon and its effects

When the two viruses infect the same cell, a virus can proliferate, while the other virus is suppressed, this phenomenon is called interference (interference), which can interfere with the proliferation of the virus known as interferon (interferon, IFN, 1957 Isaac and other in-depth study of inactivated virus can interfere with the phenomenon of live virus found interferon, it is a virus or other interferon inducer induced by human or animal cells with anti- Viruses, anti-tumor and immune regulation and other biological activity of glycoproteins. In addition to viruses, other non-viral factors (such as bacterial endotoxin), synthetic double-stranded RNA can also induce cells to produce interferon.

1. Interferon properties and different types of different sources of interferon, the relative molecular mass is also different, between 15000 ~ 25000. Interferon produced by human cells, according to their different antigen can be divided into three categories, namely, α, β, γ-IFN. α-IFN is produced by human leukocytes; β-IFN is produced by human fibroblasts; γ-IFN is produced by human T cells. α, β, γ-IFN anti-virus ability, also known as type I interferon, γ-IFN immune conditioning strong, also known as type II interferon or immune interferon.

Note: Poly I: C Polynucleotides with polypyrimidine are an artificial double-stranded RNA.

Currently using DNA recombination technology, has been cloned, homogeneous α, β, γ three interferon.

The antiviral effect of interferon is as follows. No virus specificity: a broad spectrum of antiviral effects, that is, a virus-induced interferon is effective for a variety of viruses. ② species specificity: human or primate cells produce interferon can only play an anti-viral effect on human cells, and no effect on other animals. ③ indirect play a role: interferon and antibodies, not directly on the virus, but by inducing cells to produce antiviral protein to inhibit the virus replication. ④ inhibition of cell division, maturation and differentiation: can be used for tumor treatment. ⑤ resistance to physical and chemical factors: the interference in the heat stability, 37 ℃ 24 h is not destroyed, stable at pH 2 ~ 11, lipase and nuclease is not sensitive to ultraviolet, proteolytic enzymes and trypsin sensitive.

2. Interferon induction and antiviral mechanism of the vertebrate itself has the ability to produce antiviral substances, under normal circumstances encoding the interferon gene inactivation, when the cells by the virus or induced agent (such as polyinosinic acid - Polycyclic acid, Poly I: C), triggering a series of biochemical processes such as signal transduction, leading to the expression and secretion of interferon proteins into cells; cells secreted by interferon and interferon receptor cells, But also through a series of signal transmission process to make cells express a variety of antiviral proteins, such as MixA, PRK and so on. These antiviral proteins can block viral replication and achieve viral suppression. Such as interferon-producing cells are still intact, but also make the cells to establish anti-virus state.

3. The actual significance of interferon virus infection in vivo after the interferon than specific antibodies produced earlier, therefore, to prevent the development of viral infection and promote the body has an important role in rehabilitation; interferon also has an immune regulation, can promote macrophages Phagocytosis, activation of NK cells and the role of the virus with broad spectrum. Therefore, interferon can be used for antiviral, anti-tumor therapy.