Construction and<i>In Vitro</i>Properties of HIV-1 Mutants with Deletions in "Nonessential" Genes

Gibbs, James S.; Regier, Dean A.; Desrosiers, Ronald C.

doi:10.1089/aid.1994.10.343

Cited by 160 publications

(177 citation statements)

References 56 publications

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“…HIV-1 JR-CSF Δvpu was generated by the same approach. Vpu substitutions A14L, A18H, W22A, S52,56N, and I46K were introduced into HIV-1 NL4-3 3′ (p83-10) by PCR-based mutagenesis as previously described (50). Of these Vpu changes, only the substitution at position 56 resulted in an amino acid change in Env (27).…”

Section: Methodsmentioning

confidence: 99%

Tetherin antagonism by Vpu protects HIV-infected cells from antibody-dependent cell-mediated cytotoxicity

Arias

Heyer

Bredow

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

150

161

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Significance HIV-1 viral protein U (Vpu) facilitates virus release from infected cells by down-regulating and degrading tetherin, a transmembrane protein upregulated by IFN that impedes the detachment of enveloped viruses from infected cells. Here we show that this activity of Vpu protects HIV-infected cells from antibodies that are capable of directing their elimination by antibody-dependent cell-mediated cytotoxicity. A direct implication of these observations is that tetherin serves as a link between innate and adaptive immunity to enhance the susceptibility of virus-infected cells to antibodies. Thus, the antiviral activity of tetherin may be much greater than previously appreciated based on its ability to inhibit virus release in cell culture assays.

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Section: Methodsmentioning

confidence: 99%

Tetherin antagonism by Vpu protects HIV-infected cells from antibody-dependent cell-mediated cytotoxicity

Arias

Heyer

Bredow

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

150

161

View full text Add to dashboard Cite

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“…This virus contained the recognized epitope sequences as listed for each CTL clone. In addition, p83-2.1 was also paired with the p210-5 mutant of p83-10 [36], yielding virus with a truncation of Nef after the first 12 aa (HIV-1/~Nef), or a mutant of p83-10 containing an AT to GC mutation at nucleotides 8844-8845 of NL4-3 leading to a methionine to alanine mutation at aa 20 of Nef (HIV-1/M20A). For the MHC-I down-regulation experiment, a p83-2 construct containing the murine CD24 reporter gene was co-transfected with p83-10 Nef variants to produce reporter versions of these viruses, are previously described [35].…”

Section: Hiv-1 Stocksmentioning

confidence: 99%

Evasion of cytotoxic T lymphocytes is a functional constraint maintaining HIV-1 Nef expression

Ali

Dagarag

et al. 2005

Eur. J. Immunol.

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Nef expression is not required for HIV-1 replication and is highly targeted by CD8 + CTL, raising the question of why Nef expression is not lost in order to evade immunity in vivo. We explore whether MHC class I (MHC-I) down-regulation to evade CTL in general is a selective pressure maintaining Nef. HIV-1 with functional Nef (wild type, WT) is compared to virus containing a Nef point mutation (M20A) that selectively ablates MHC-I down-regulation. WT-infected cells are relatively resistant to cytolysis and less suppressed for viral replication by Gag-and RT-specific CTL compared to M20A. These viruses grow similarly in vitro in the absence of CTL, but the presence of Gag-or RTspecific CTL strongly favors WT overgrowth of M20A. Finally, while in vitro selection by Nef-specific CTL readily drives disruption of the nef reading frame, the addition of Gagor RT-specific CTL markedly limits such escape. These data indicate that MHC-I downregulation is an important function favoring Nef maintenance due to a net selective advantage in the setting of the general CTL response.

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“…NL4-3 (17) variants were produced by coelectroporation of H9 cells with p83-2 and p83-10 plasmid variants linearized with EcoRI, according to the method described by Gibbs and Desrosiers (18). All plasmids were confirmed by sequencing.…”

Section: Hiv-1 Stocksmentioning

confidence: 99%

Broadly Increased Sensitivity to Cytotoxic T Lymphocytes Resulting from Nef Epitope Escape Mutations

Ali

Pillai

et al. 2003

The Journal of Immunology

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Nef is an HIV-1 protein that is absent in most retroviruses, yet its reading frame is highly maintained despite frequent targeting by CD8+ CTL in vivo. Because Nef is not necessarily required for viral replication, this consistent maintenance suggests that Nef plays an important role(s) and substantial fitness constraints prevent its loss in vivo. The ability of Nef to down-regulate cell surface MHC class I (MHC-I) molecules and render infected cells resistant to CTL in general is likely to be an important contributing function. We demonstrate that mutational escape of HIV-1 from Nef-specific CTL in vitro leads to progeny virions that are increased in their susceptibility to CTL of specificities for proteins other than Nef. The escape mutants contain multiple nef mutations that impair the ability of the virus to down-regulate MHC-I through disruption of its reading frame as well as epitope point mutations. Given the rarity of nef frameshifts in vivo, these data support the concept that the ability to down-regulate MHC-I could be a key constraint for preservation of Nef in vivo.

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Construction andIn VitroProperties of HIV-1 Mutants with Deletions in "Nonessential" Genes

Cited by 160 publications

References 56 publications

Tetherin antagonism by Vpu protects HIV-infected cells from antibody-dependent cell-mediated cytotoxicity

Tetherin antagonism by Vpu protects HIV-infected cells from antibody-dependent cell-mediated cytotoxicity

Evasion of cytotoxic T lymphocytes is a functional constraint maintaining HIV-1 Nef expression

Broadly Increased Sensitivity to Cytotoxic T Lymphocytes Resulting from Nef Epitope Escape Mutations

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