Interferon

Interferon type I (α/β/δ...)
The molecular structure of human interferon-alpha (PDB: 1RH2​)
Identifiers
SymbolInterferons
PfamPF00143
InterProIPR000471
SMARTSM00076
PROSITEPDOC00225
CATH1au0
SCOP21au1 / SCOPe / SUPFAM
CDDcd00095
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Interferon type II (γ)
The three-dimensional structure of human interferon gamma (PDB: 1HIG​)
Identifiers
SymbolIFN-gamma
PfamPF00714
InterProIPR002069
CATH1d9cA00
SCOP2d1d9ca_ / SCOPe / SUPFAM
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Interferon type III (λ)
Identifiers
SymbolIL28A
PfamPF15177
InterProIPR029177
CATH3og6A00
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

Interferons (IFNs, /ˌɪntərˈfɪərɒn/ IN-tər-FEER-on[1]) are a group of signaling proteins[2] made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.

IFNs belong to the large class of proteins known as cytokines, molecules used for communication between cells to trigger the protective defenses of the immune system that help eradicate pathogens.[3] Interferons are named for their ability to "interfere" with viral replication[3] by protecting cells from virus infections. However, virus-encoded genetic elements have the ability to antagonize the IFN response, contributing to viral pathogenesis and viral diseases.[4] IFNs also have various other functions: they activate immune cells, such as natural killer cells and macrophages, and they increase host defenses by up-regulating antigen presentation by virtue of increasing the expression of major histocompatibility complex (MHC) antigens. Certain symptoms of infections, such as fever, muscle pain and "flu-like symptoms", are also caused by the production of IFNs and other cytokines.

More than twenty distinct IFN genes and proteins have been identified in animals, including humans. They are typically divided among three classes: Type I IFN, Type II IFN, and Type III IFN. IFNs belonging to all three classes are important for fighting viral infections and for the regulation of the immune system.

  1. ^ "Interferon | Definition of Interferon by Lexico". Archived from the original on 2020-12-22. Retrieved 2019-10-17.
  2. ^ De Andrea M, Ravera R, Gioia D, Gariglio M, Landolfo S (2002). "The interferon system: an overview". European Journal of Paediatric Neurology. 6 Suppl A (6): A41–6, discussion A55–8. doi:10.1053/ejpn.2002.0573. PMID 12365360. S2CID 4523675.
  3. ^ a b Parkin J, Cohen B (June 2001). "An overview of the immune system". Lancet. 357 (9270): 1777–89. doi:10.1016/S0140-6736(00)04904-7. PMID 11403834. S2CID 165986.
  4. ^ Elrefaey, Ahmed M. E.; Hollinghurst, Philippa; Reitmayer, Christine M.; Alphey, Luke; Maringer, Kevin (November 2021). "Innate Immune Antagonism of Mosquito-Borne Flaviviruses in Humans and Mosquitoes". Viruses. 13 (11): 2116. doi:10.3390/v13112116. PMC 8624719. PMID 34834923.