7/25/2019 Interferons Type II & III

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CATEGORY: RECEPTORS & MOLECULES

Interferons: Type II & IIIEllen Margaret Moran, Charles Institute ofDermatology, University College Dublin, Ireland

Interferons: Type II & III

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Table 1. Members of the Type II and III Interferon Family

Interferons were first described in the late 1950s by two scientists Isaacs and Lindenmann who

assigned an antiviral factor the name interferon. This was due to the molecules ability to interfere

with the growth of the influenza virus. In the subsequent twenty years, the type I interferon family

comprising key members such as IFN- and IFN- was well characterised. The type I interferons are

considered the first line of defence against numerous viral infections in humans.

Two additional interferon subtypes have also been identified as being biologically significant: type II

interferon or IFN- and the type III interferons IFN-1, IFN-2 and IFN-3. IFN- is secreted by natural

killer (NK) cells, T cells and antigen presenting cells (monocytes, macrophages and dendritic cells)

whereas to date the only source of type III interferons identified is plasmacytoid dendritic cells (DCs).

IFN- was initially described as an antiviral factor, however, it has since been demonstrated to

contribute to a much wider range of biological activities. Binding of IFN- to its receptors promotes

cellular immune responses; activation of macrophages and NK cells; upregulation of MHC expression

and promoting leucocyte migration. IFN- is also considered the key cytokine in the Th1 immune

response.

Type III interferons are co-expressed with type I interferons by virally infected cells and both contribute

to the early antiviral response. In addition, type III IFNs are capable of modulating the adaptive immune

response. IFN- increases MHC I and II expression on DCs as well as levels of CCR7, the chemokine

receptor crucial for DC migration to lymph nodes.

The broad functions of the interferon family are evidenced by the treatments currently in use and/or in

development that modulate the various members for the treatment of diseases such as chronic

hepatitis C infection and multiple sclerosis..

Members Cellular

source

Functions

Type II IFN- NK cells,

T cells,

antigen

presenting

cells

- Activates macrophages and NK cells

-Upregulation of MHC expression

- Drives leucocyte migration

- Mediator of Th1 immune response

Type III IFN- 1, IFN-2, IFN-

3

Plasmacytoid

DCs

- Upregulation of DC MHC I and II

expression

- Modulation of CCR7 mediated DC

migration