title: MxB Is Not Responsible for the Blocking of HIV-1 Infection Observed in Alpha Interferon-Treated Cells.
abstract: MxB restricts HIV-1 infection by directly interacting with the HIV-1 core, which is made of viral capsid; however, the contribution of MxB to the HIV-1 restriction observed in alpha interferon (IFN-α)-treated human cells is unknown. To understand this contribution, we used HIV-1 bearing the G208R capsid mutant (HIV-1-G208R), which overcomes the restriction imposed by cells expressing MxB. Here we showed that the reason why MxB does not block HIV-1-G208R is that MxB does not interact with HIV-1 cores bearing the mutation G208R. To understand whether MxB contributes to the HIV-1 restriction imposed by IFN-α-treated human cells, we challenged IFN-α-treated cells with HIV-G208R and found that MxB does not contribute to the restriction imposed by IFN-α-treated cells. To more directly test the contribution of MxB, we challenged IFN-α-treated human cells that are knocked out for the expression of MxB with HIV-1. These experiments suggested that MxB does not contribute to the HIV-1 restriction observed in IFN-α-treated human cells.
  
  
  OBJECTIVE
  MxB is a restriction factor that blocks HIV-1 infection in human cells. Although it has been postulated that MxB is the factor that blocks HIV-1 infection in IFN-α-treated cells, this is a hard concept to grasp due to the great number of genes that are induced by IFN-α in cells from the immune system. The work presented here elegantly demonstrates that MxB has minimal or no contribution to the ability of IFN-α-treated human cells to block HIV-1 infection. Furthermore, this work suggests the presence of novel restriction factors in IFN-α-treated human cells that block HIV-1 infection.
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Silvana
authors.initials: S
authors.lastname: Opp
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Daniel A S A
authors.initials: DA
authors.lastname: Vieira
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Bianca
authors.initials: B
authors.lastname: Schulte
authors.affiliation: Immunity and Pathogenesis Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
authors.forename: Sumit K
authors.initials: SK
authors.lastname: Chanda
authors.affiliation: Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA Felipe.Diaz-Griffero@einstein.yu.edu.
authors.forename: Felipe
authors.initials: F
authors.lastname: Diaz-Griffero
mesh_terms: D002460:Cell Line; D055786:Gene Knockout Techniques; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016898:Interferon-alpha / Q000378:metabolism*; D064547:Myxovirus Resistance Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D016898:Interferon-alpha; C579068:MX2 protein, human; D064547:Myxovirus Resistance Proteins