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. Author manuscript; available in PMC: 2012 Oct 16.
Published in final edited form as: Transl Biomed. 2010;1(2):172.

Table 5.

Host immune functions affected by KSHV (reviewed in [152])

Interfron response
 vIRF1 (K9)

  • A homologue of the cellular interferon regulatory factors

  • Inhibits IFNα and IFNβ via interaction with CBP/p300

  • Reduces IRF-1 transcriptional activity

 vIRF-2 (K11 and 11.1)

  • Inhibits Type I IFN by inactivating IRF-1 and IRF-3

  • Inactivates the IFN response protein protein kinase R (PKR)

 vIRF-3 (LANA-2, K10.5 and K10.6)

  • Binds and inactivates p53

  • Effect on IFNα expression is unclear

  • Detected in PEL and MCD-derived B cells, but not KS tumors or infected endothelial cells

 vIRF-4 (K10/10.1)

  • Does not suppress IFNβ promoter activity but may interact with the Poly(A)-binding protein (PABP) [153].

  • Inhibits p53 via interaction with murine double mutant 2 (MDM2) [61]

 ORF45

  • Inhibits IRF-7

 RTA (ORF 50)

  • Induces degradation of IRF-7 [154]

 vIL-6 (K2)

  • A constitutive homologue of IL-6

  • Blocks IFNα signaling in PEL cells [155]

 LANA-1 (ORF73)

  • Inhibits IFNβ by blocking IRF-3 binding to IFNβ promoter [156]

 KSHV binding

  • suppresses p300 by upregulating the cellular microRNA miR-132 [157]

Complement response
 ORF 4 (KCP)

  • KSHV complement-control protein [158]

  • Inhibits complement cascade [159]

MHC-1 downregulation
 MIR1 (modulators of immune recognition) (K3)

  • E3 ubiquitin ligase

  • Induces degradation of MHC-1 (HLA-A, -B, -C and –E)

  • Downregulates CD1d and IFNγ receptor

 MIR2 (K5)

  • E3 ubiquitin ligase

  • Induces degradation of MHC-1 (HLA-A, and –B)

  • Downregulates ICAM-1 and B7.2, which inhibits NK killing [160]

  • Downregulates CD1d [161], IFNγ receptor, CD31 [162], bone marrow stromal antigen 2 (tetherin) [163, 164], activated leukocyte cell adhesion molecule (CD166, a ligand for CD6) and Syntaxin-4 [163]

 vIRF-1 (K9)

  • Decreases transcription of MHC-1[165]