Recognition of Escape Variants in ELISPOT Does Not Always Predict CD8
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            T-Cell Recognition of Simian Immunodeficiency Virus-Infected Cells Expressing the Same Variant Sequences

Valentine, Laura E.; Piaskowski, Shari M.; Rakasz, Eva G.; Henry, Nathan L.; Wilson, Nancy A.; Watkins, David I.

doi:10.1128/jvi.00275-07

Cited by 40 publications

(46 citation statements)

References 39 publications

(64 reference statements)

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“…ϩ T cell responses to smallpox and yellow fever virus vaccinations, measured by cellular activation, intracellular cytokine staining, and tetramer frequencies, revealed that these responses are of a much higher magnitude than was previously appreciated (34). While assessments of HIV-specific responses have traditionally relied on assays that measure IFN-␥ secretion, this cytokine does not always correlate with protective immunity, nor does it accurately describe the full breadth of HIV-specific CD8 ϩ T cell responses (15,26,45). Other studies have demonstrated that HIV ϩ LTNP maintain a more functional response than do those who progress to AIDS (1,5), but whether these responses differ in specificity remains largely unexplored.…”

Section: Fig 3 Hiv-specific Cd8mentioning

confidence: 99%

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Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Richmond

McKinnon

Kiazyk

et al. 2011

J Virol

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The limited success of HIV vaccine candidates to date highlights our need to better characterize protective cell-mediated immunity (CMI). While HIV-specific CD8؉ T cell responses have been defined largely by measuring gamma interferon (IFN-␥), these responses are not always protective, and it is unclear whether the same epitopes would predominate if other functional parameters were examined. Here, we assessed the epitope specificity of HIV-specific CD8 responses). Many responses had polyfunctional (33%) and proliferative (19%) components. An inverse association between IL-2 and proliferation responses was also observed, contrary to what was described previously. We confirm that long-term nonprogressors (LTNP) have more polyfunctional responsesand also have higher-magnitude and broader p24-specific proliferation and higher levels of IL-2 and TNF-␣ production than do progressing controls. Together, these data suggest that the specificity of CD8 ؉ T cell responses differs depending on the immunological readout, with a 3.5-fold increase in breadth detected by including multiple parameters. Furthermore, the identification of epitopes that elicit polyfunctional responses reinforces the need for the comprehensive evaluation of HIV vaccine candidates, and these epitopes may represent novel targets for CMI-based vaccines.

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Section: Fig 3 Hiv-specific Cd8mentioning

confidence: 99%

“…Recent studies have begun to call into question the reliability of ELISPOT assays for the assessment effective immune responses (4,45,47). The use of a single readout may miss many effective responses, particularly a readout that may not measure responses capable of controlling HIV infection.…”

mentioning

confidence: 99%

Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Richmond

McKinnon

Kiazyk

et al. 2011

J Virol

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“…However, to date there has been no evaluation of HIV-1-infected cellrecognizing CTL responses in rAd5 vaccinees. This is more than an academic distinction; it has been demonstrated that CTL can recognize exogenously-loaded HIV-1 peptides despite being unable to recognize HIV-1-infected cells with the same epitope sequences [11,16,17]. The mechanism relates to the difference between excess peptides used for detection assays versus lower levels of endogenously-produced epitopes on HIV-1-infected cells, with insufficient CTL avidity to recognize physiologic levels of epitopes [16,17].…”

Section: Recognition Of Excess Peptide-loaded Target Cells Versus Hivmentioning

confidence: 99%

“…This assay provided the data that served as the basis for advancement of rAd5 into phase II human trials. However, ELISpot does not provide measurements that clearly correlate to immune control within infected persons, likely because it does not reflect antiviral function [10,11]. Measurements of CTL "polyfunctionality" via intracellular cytokine staining for multiple cytokines are under development for vaccine trial evaluation because polyfunctionality correlates to good immune control in HIV-1-infected persons [12], but it remains to be determined whether this is cause or effect, and whether polyfunctionality of CTL would predict protection by a vaccine [13].…”

Section: Requirements For Ctl Antiviral Functionmentioning

confidence: 99%

Section: Requirements For Ctl Antiviral Functionmentioning

confidence: 99%

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Retracing our STEP towards a successful CTL-based HIV-1 vaccine

Yang

2008

Vaccine

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The September 21 st announcement that the STEP study (of the recombinant Adenovirus serotype 5, rAd5 HIV-1 vaccine) was being halted for futility [1] was a serious setback in the quest for a vaccine to prevent or attenuate HIV-1 infection. The rAd5 vaccine (with or without DNA vaccine priming) had been the only strategy demonstrating apparently consistent immunogenicity for HIV-1-specific CD8 + T lymphocyte (CTL) responses in humans. This vaccine approach was held as the major hope for a strategy that would show some efficacy in human trials, to serve as a proof-of-concept working prototype vaccine to be refined and improved. This hope was dashed when interim analysis revealed 21/762 versus 24/741 infections in the placebo and vaccine groups respectively, with set-point viremia levels also being similar (37,000 versus 40,000 genomes/ml plasma respectively). Does this result indicate that a CTL-based vaccine is not the right approach? To date, the CTL response has been the only arm of adaptive immunity that has been clearly linked to control (albeit partial) of HIV-1 replication in vivo, as demonstrated by CTL being the major selective force for viral sequence evolution [2][3][4], and suggested by an inverse correlation of bulk CTL levels with viremia during CD8 depletion in the SIV-macaque model [5][6][7]. Such observations have been the basis for pursuing the CTL-based approach. The STEP study was pursued based on the apparent ability of the rAd5 vaccine to elicit HIV-1-specific CTL responses. Does the negative finding in this study indicate that a CTL-based approach is not a viable solution for a vaccine? Alternatively, is this a failure of the current vaccine to elicit functional CTL? Requirements for CTL antiviral functionUnfortunately, a clear "correlate of immunity" based on any existing CTL measurements is lacking. To date, the interferon-γ ELISpot is the only validated assay for HIV-1 vaccine trials [8,9], by nature of its ease, reproducibility, and quantitative precision in mapping the targeting and magnitude of CTL responses. This assay provided the data that served as the basis for advancement of rAd5 into phase II human trials. However, ELISpot does not provide measurements that clearly correlate to immune control within infected persons, likely because it does not reflect antiviral function [10,11]. Measurements of CTL "polyfunctionality" via

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Development of a luciferase based viral inhibition assay to evaluate vaccine induced CD8 T-cell responses

Naarding

Fernández

Kappes

et al. 2014

Journal of Immunological Methods

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Emergence of SIV and HIV specific CD8 T cells has been shown to correlate with control of in vivo replication. Poor correlation between IFN-γ ELISPOT responses and in vivo control of the virus has triggered the development of more relevant assays to assess functional HIV-1 specific CD8 T-cell responses for the evaluation and prioritization of new HIV-1 vaccine candidates. We previously established a viral inhibition assay (VIA) that measures the ability of vaccine-induced CD8 T-cell responses to inhibit viral replication in autologous CD4 T cells. In this assay, viral replication is determined by measuring p24 in the culture supernatant. Here we describe the development of a novel VIA, referred to as IMC LucR VIA that exploits replication-competent HIV-1 infectious molecular clones (IMCs) in which the complete proviral genome is strain-specific and which express the Renilla luciferase (LucR) gene to determine viral growth and inhibition. The introduction of the luciferase readout does provide significant improvement of the read out time. In addition to switching to the LucR read out, changes made to the overall protocol resulted in the miniaturization of the assay from a 48 to a 96-well plate format, which preserved sample and allowed for the introduction of replicates. The overall assay time was reduced from 13 to 8 days. The assay has a high degree of specificity, and the previously observed non-specific background inhibition in cells from HIV-1 negative volunteers has been reduced dramatically. Importantly, we observed an increase in positive responses, indicating an improvement in sensitivity compared to the original VIA. Currently, only a limited number of “whole-genome” IMC-LucR viruses are available and our efforts will focus on expanding the panel to better evaluate anti-viral breadth. Overall, we believe the IMC LucR VIA provides a platform to assess functional CD8 T-cell responses in large-scale clinical trial testing, which will enhance the ability to select the most promising HIV-1 vaccine candidates capable of controlling HIV-1 replication in vivo.

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Recognition of Escape Variants in ELISPOT Does Not Always Predict CD8 ⁺ T-Cell Recognition of Simian Immunodeficiency Virus-Infected Cells Expressing the Same Variant Sequences

Abstract: Human immunodeficiency virus (HIV)'

Cited by 40 publications

References 39 publications

Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Retracing our STEP towards a successful CTL-based HIV-1 vaccine

Development of a luciferase based viral inhibition assay to evaluate vaccine induced CD8 T-cell responses

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Recognition of Escape Variants in ELISPOT Does Not Always Predict CD8 + T-Cell Recognition of Simian Immunodeficiency Virus-Infected Cells Expressing the Same Variant Sequences

Abstract: Human immunodeficiency virus (HIV)'

Cited by 40 publications

References 39 publications

Epitope Mapping of HIV-Specific CD8 + T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Epitope Mapping of HIV-Specific CD8 + T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Retracing our STEP towards a successful CTL-based HIV-1 vaccine

Development of a luciferase based viral inhibition assay to evaluate vaccine induced CD8 T-cell responses

Contact Info

Product

Resources

About

Recognition of Escape Variants in ELISPOT Does Not Always Predict CD8 ⁺ T-Cell Recognition of Simian Immunodeficiency Virus-Infected Cells Expressing the Same Variant Sequences

Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function

Epitope Mapping of HIV-Specific CD8 ⁺ T Cell Responses by Multiple Immunological Readouts Reveals Distinct Specificities Defined by Function