Viruses are obligatory intracellular parasites. Most of the cells in animaland human body possess the innate ability to fight viruses. Innate immune function restrictsinfection at the early stage and delay spread of v...Viruses are obligatory intracellular parasites. Most of the cells in animaland human body possess the innate ability to fight viruses. Innate immune function restrictsinfection at the early stage and delay spread of virus. The early stage of infection is the stage ofinteraction between the virus and the host's defence system. Once the latter is breached, the earlynon-specific or innate immune components such as interferon (IFN), natural killer (NK) cells andmacrophages become active. As the infection proceeds, the adaptive (specific) immune responsedevelops, with the appearance of cytotoxic T cells, helper T cells and antiviral antibodies.Antibodies provide a major barrier to virus spread between cells and cells and are particularlyimportant in restriction of virus spread in the blood stream. Virus infection directly activates thetranscription of type Ⅰ IFN (IFN-alfa/beta) genes in infected cells, while the type Ⅱ IFN(IFN-gamma) plays an essential role in the regulation of an adaptive immune response rather thaninnate immune response. Therefore, Type Ⅰ IFN is the first defence for host and neighbouring cellsto resist virus infection.展开更多
文摘Viruses are obligatory intracellular parasites. Most of the cells in animaland human body possess the innate ability to fight viruses. Innate immune function restrictsinfection at the early stage and delay spread of virus. The early stage of infection is the stage ofinteraction between the virus and the host's defence system. Once the latter is breached, the earlynon-specific or innate immune components such as interferon (IFN), natural killer (NK) cells andmacrophages become active. As the infection proceeds, the adaptive (specific) immune responsedevelops, with the appearance of cytotoxic T cells, helper T cells and antiviral antibodies.Antibodies provide a major barrier to virus spread between cells and cells and are particularlyimportant in restriction of virus spread in the blood stream. Virus infection directly activates thetranscription of type Ⅰ IFN (IFN-alfa/beta) genes in infected cells, while the type Ⅱ IFN(IFN-gamma) plays an essential role in the regulation of an adaptive immune response rather thaninnate immune response. Therefore, Type Ⅰ IFN is the first defence for host and neighbouring cellsto resist virus infection.
