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Interferon-α Subtypes in an Ex Vivo Model of Acute HIV-1 Infection: Expression, Potency and Effector Mechanisms.

Harper MS, Guo K, Gibbert K, Lee EJ, Dillon SM, Barrett BS, McCarter MD, Hasenkrug KJ, Dittmer U, Wilson CC, Santiago ML - PLoS Pathog. (2015)

Bottom Line: The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D.However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity.By contrast, both potent (IFNα8) and weak (IFNα1) subtypes significantly induced HIV-1 GG-to-AG hypermutation.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America; Department of Immunology and Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
HIV-1 is transmitted primarily across mucosal surfaces and rapidly spreads within the intestinal mucosa during acute infection. The type I interferons (IFNs) likely serve as a first line of defense, but the relative expression and antiviral properties of the 12 IFNα subtypes against HIV-1 infection of mucosal tissues remain unknown. Here, we evaluated the expression of all IFNα subtypes in HIV-1-exposed plasmacytoid dendritic cells by next-generation sequencing. We then determined the relative antiviral potency of each IFNα subtype ex vivo using the human intestinal Lamina Propria Aggregate Culture model. IFNα subtype transcripts from the centromeric half of the IFNA gene complex were highly expressed in pDCs following HIV-1 exposure. There was an inverse relationship between IFNA subtype expression and potency. IFNα8, IFNα6 and IFNα14 were the most potent in restricting HIV-1 infection. IFNα2, the clinically-approved subtype, and IFNα1 were both highly expressed but exhibited relatively weak antiviral activity. The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D. However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity. By contrast, both potent (IFNα8) and weak (IFNα1) subtypes significantly induced HIV-1 GG-to-AG hypermutation. The results unravel non-redundant functions of the IFNα subtypes against HIV-1 infection, with strong implications for HIV-1 mucosal immunity, viral evolution and IFNα-based functional cure strategies.

No MeSH data available.


Related in: MedlinePlus

Inhibition of HIV-1 by 12 IFNα subtypes in the LPAC model.(A) LPMCs (n = 4 donors) were infected with HIV-1BaL (10 ng p24/106 cells) by spinoculation for 2 hrs. Each IFNα subtype was added individually at 100 pg/ml, and cells were harvested at 4dpi. (B) Dose-response curve of IFNα14 for inhibition of HIV-1 infection (p24+CD3+/CD8- lymphocytes). Vertical dashed line indicates the IFNα dose used for subsequent experiments. Inhibition of (C) cellular HIV-1 infection and (D) infectious titer, normalized to untreated samples. Bars correspond to the means with SEM error bars from 4 LPMC donors. The x-axis was arranged from the least to the most potent IFNα subtype. Repeated measures ANOVA with Dunnett’s multiple comparison test was performed on raw infection values. Pairwise comparisons were each against the no IFNα control. ns, not significant at p>0.05; *, p<0.05; **, p<0.01; ***, p<0.001.
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ppat.1005254.g002: Inhibition of HIV-1 by 12 IFNα subtypes in the LPAC model.(A) LPMCs (n = 4 donors) were infected with HIV-1BaL (10 ng p24/106 cells) by spinoculation for 2 hrs. Each IFNα subtype was added individually at 100 pg/ml, and cells were harvested at 4dpi. (B) Dose-response curve of IFNα14 for inhibition of HIV-1 infection (p24+CD3+/CD8- lymphocytes). Vertical dashed line indicates the IFNα dose used for subsequent experiments. Inhibition of (C) cellular HIV-1 infection and (D) infectious titer, normalized to untreated samples. Bars correspond to the means with SEM error bars from 4 LPMC donors. The x-axis was arranged from the least to the most potent IFNα subtype. Repeated measures ANOVA with Dunnett’s multiple comparison test was performed on raw infection values. Pairwise comparisons were each against the no IFNα control. ns, not significant at p>0.05; *, p<0.05; **, p<0.01; ***, p<0.001.

Mentions: Since the GALT is the major site of early HIV-1 amplification and spread, we utilized LPAC as a physiologically relevant model to determine the relative anti-HIV potency of each IFNα subtype. In particular, we were interested in whether IFNα2, the subtype approved for clinical use, was the optimal IFNα subtype for inhibiting HIV-1. Fig 2A outlines the experimental infection protocol.


Interferon-α Subtypes in an Ex Vivo Model of Acute HIV-1 Infection: Expression, Potency and Effector Mechanisms.

Harper MS, Guo K, Gibbert K, Lee EJ, Dillon SM, Barrett BS, McCarter MD, Hasenkrug KJ, Dittmer U, Wilson CC, Santiago ML - PLoS Pathog. (2015)

Inhibition of HIV-1 by 12 IFNα subtypes in the LPAC model.(A) LPMCs (n = 4 donors) were infected with HIV-1BaL (10 ng p24/106 cells) by spinoculation for 2 hrs. Each IFNα subtype was added individually at 100 pg/ml, and cells were harvested at 4dpi. (B) Dose-response curve of IFNα14 for inhibition of HIV-1 infection (p24+CD3+/CD8- lymphocytes). Vertical dashed line indicates the IFNα dose used for subsequent experiments. Inhibition of (C) cellular HIV-1 infection and (D) infectious titer, normalized to untreated samples. Bars correspond to the means with SEM error bars from 4 LPMC donors. The x-axis was arranged from the least to the most potent IFNα subtype. Repeated measures ANOVA with Dunnett’s multiple comparison test was performed on raw infection values. Pairwise comparisons were each against the no IFNα control. ns, not significant at p>0.05; *, p<0.05; **, p<0.01; ***, p<0.001.
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Related In: Results  -  Collection

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ppat.1005254.g002: Inhibition of HIV-1 by 12 IFNα subtypes in the LPAC model.(A) LPMCs (n = 4 donors) were infected with HIV-1BaL (10 ng p24/106 cells) by spinoculation for 2 hrs. Each IFNα subtype was added individually at 100 pg/ml, and cells were harvested at 4dpi. (B) Dose-response curve of IFNα14 for inhibition of HIV-1 infection (p24+CD3+/CD8- lymphocytes). Vertical dashed line indicates the IFNα dose used for subsequent experiments. Inhibition of (C) cellular HIV-1 infection and (D) infectious titer, normalized to untreated samples. Bars correspond to the means with SEM error bars from 4 LPMC donors. The x-axis was arranged from the least to the most potent IFNα subtype. Repeated measures ANOVA with Dunnett’s multiple comparison test was performed on raw infection values. Pairwise comparisons were each against the no IFNα control. ns, not significant at p>0.05; *, p<0.05; **, p<0.01; ***, p<0.001.
Mentions: Since the GALT is the major site of early HIV-1 amplification and spread, we utilized LPAC as a physiologically relevant model to determine the relative anti-HIV potency of each IFNα subtype. In particular, we were interested in whether IFNα2, the subtype approved for clinical use, was the optimal IFNα subtype for inhibiting HIV-1. Fig 2A outlines the experimental infection protocol.

Bottom Line: The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D.However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity.By contrast, both potent (IFNα8) and weak (IFNα1) subtypes significantly induced HIV-1 GG-to-AG hypermutation.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America; Department of Immunology and Microbiology, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
HIV-1 is transmitted primarily across mucosal surfaces and rapidly spreads within the intestinal mucosa during acute infection. The type I interferons (IFNs) likely serve as a first line of defense, but the relative expression and antiviral properties of the 12 IFNα subtypes against HIV-1 infection of mucosal tissues remain unknown. Here, we evaluated the expression of all IFNα subtypes in HIV-1-exposed plasmacytoid dendritic cells by next-generation sequencing. We then determined the relative antiviral potency of each IFNα subtype ex vivo using the human intestinal Lamina Propria Aggregate Culture model. IFNα subtype transcripts from the centromeric half of the IFNA gene complex were highly expressed in pDCs following HIV-1 exposure. There was an inverse relationship between IFNA subtype expression and potency. IFNα8, IFNα6 and IFNα14 were the most potent in restricting HIV-1 infection. IFNα2, the clinically-approved subtype, and IFNα1 were both highly expressed but exhibited relatively weak antiviral activity. The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D. However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity. By contrast, both potent (IFNα8) and weak (IFNα1) subtypes significantly induced HIV-1 GG-to-AG hypermutation. The results unravel non-redundant functions of the IFNα subtypes against HIV-1 infection, with strong implications for HIV-1 mucosal immunity, viral evolution and IFNα-based functional cure strategies.

No MeSH data available.


Related in: MedlinePlus