Infected cell protein 47
{{Infobox protein family
|Symbol=Herpes_US12
|Name=US12
|InterPro=IPR008026
|Pfam=PF05363
|SCOP=1qlo
|CATH=5U1D
}}
Infected cell protein 47 also ICP-47 or ICP47 is a protein encoded by the viruses such as Herpes simplex virus and Cytomegalovirus that allows them to evade the human immune system's CD8 T-cell response by interfering with an infected cell's ability to show viral epitopes to T cells.{{cite journal | vauthors = Goldsmith K, Chen W, Johnson DC, Hendricks RL | title = Infected cell protein (ICP)47 enhances herpes simplex virus neurovirulence by blocking the CD8+ T cell response | journal = The Journal of Experimental Medicine | volume = 187 | issue = 3 | pages = 341–8 | date = February 1998 | pmid = 9449714 | pmc = 2212130 | doi = 10.1084/jem.187.3.341 | citeseerx = 10.1.1.282.6406 }} Its secondary structure shows three helices.
Method of action
It works by inhibiting transfer of viral particles to the human TAP proteins and thus entry of viral peptides into the endoplasmic reticulum, which is supposed to bind them to MHC class I molecules for extracellular T-cell recognition so the viral component will trigger immune defense response as a foreign entity.{{cite journal | vauthors = Berger C, Xuereb S, Johnson DC, Watanabe KS, Kiem HP, Greenberg PD, Riddell SR | title = Expression of herpes simplex virus ICP47 and human cytomegalovirus US11 prevents recognition of transgene products by CD8(+) cytotoxic T lymphocytes | journal = Journal of Virology | volume = 74 | issue = 10 | pages = 4465–73 | date = May 2000 | pmid = 10775582 | pmc = 111967 | doi = 10.1128/jvi.74.10.4465-4473.2000 }} However human or some animal TAP proteins differs in mice making rodents far less susceptible than humans to HSV.