08-24-2013, 07:05 AM
Interferon Mode of Action:
Interferons are released by macrophages, lymphocytes and tissue cells infected with a virus. When interferon reacts with the interferon receptors of a cell, the cell enters in a state called interferon-induced antiviral state. In this state, a rapid degradation of mRNA occurs if the cell is infected by any virus. Interferon induces in cells the production of 2, 5-adenosine polymerase. When such a cell is infected by a virus, the 2, 5-adenosine polymerase is activated to produce 2, 5-adenosine polymerase, which in turn activates pre-existing, but inactive, molecules of ribonuclease-L. Activated ribonuclease-L degrades all mRNAs (of host as well as virus origin) present in the cell bringing the protein synthesis to a halt in such cells. This interferes with multiplication of the virus so that virus infection is either stopped or sufficiently slowed down to allow the production of adequate antibodies against the invading virus. The protection due to interferons is nonspecific in that interferon induced by any one virus will provide protection against all viruses. It is possible that interferons modify ribosomes so that they no longer translate viral mRNAs, although they are fully capable of translating mRNAs of the host origin.
Interferons enhance the cytotoxic activity of natural killer cells (NK cells) which are a type of lymphocytes identifiable as large granular lymphocytes. Interferons are known to inhibit growth of some types of tumors; most of these tumors are also responsive to chemotherapy.
Production of recombinant interferons (General protocol):
Interferons are produced from human leucocytes isolated from donor blood and cultured in vitro, and from mouse fibroblast cultures. Large scale (1000 l to 10,000 l) cell cultures are infected with Sendai virus, and incubated for 24 hr, after which the supernatant (clear fluid) is collected, centrifuged, and used for interferon isolation. The amount of interferon recovered is relatively small (1g interferon of low purity from leucocytes separated from blood of about 90,000 donors), and the normal leucocytes are difficult to culture preventing scaling up from relatively small inoculate.
Interferons are released by macrophages, lymphocytes and tissue cells infected with a virus. When interferon reacts with the interferon receptors of a cell, the cell enters in a state called interferon-induced antiviral state. In this state, a rapid degradation of mRNA occurs if the cell is infected by any virus. Interferon induces in cells the production of 2, 5-adenosine polymerase. When such a cell is infected by a virus, the 2, 5-adenosine polymerase is activated to produce 2, 5-adenosine polymerase, which in turn activates pre-existing, but inactive, molecules of ribonuclease-L. Activated ribonuclease-L degrades all mRNAs (of host as well as virus origin) present in the cell bringing the protein synthesis to a halt in such cells. This interferes with multiplication of the virus so that virus infection is either stopped or sufficiently slowed down to allow the production of adequate antibodies against the invading virus. The protection due to interferons is nonspecific in that interferon induced by any one virus will provide protection against all viruses. It is possible that interferons modify ribosomes so that they no longer translate viral mRNAs, although they are fully capable of translating mRNAs of the host origin.
Interferons enhance the cytotoxic activity of natural killer cells (NK cells) which are a type of lymphocytes identifiable as large granular lymphocytes. Interferons are known to inhibit growth of some types of tumors; most of these tumors are also responsive to chemotherapy.
Production of recombinant interferons (General protocol):
Interferons are produced from human leucocytes isolated from donor blood and cultured in vitro, and from mouse fibroblast cultures. Large scale (1000 l to 10,000 l) cell cultures are infected with Sendai virus, and incubated for 24 hr, after which the supernatant (clear fluid) is collected, centrifuged, and used for interferon isolation. The amount of interferon recovered is relatively small (1g interferon of low purity from leucocytes separated from blood of about 90,000 donors), and the normal leucocytes are difficult to culture preventing scaling up from relatively small inoculate.
![[+]](https://www.biotechnologyforums.com/images/netpen-pro/collapse_collapsed.png)