The cationic region from HIV tat enhances the cell-surface expression of epitope/MHC class I complexes

J. A. Leifert, P. D. Holler, S. Harkins, David M Kranz, J. L. Whitton

Research output: Contribution to journalArticle

Abstract

The potential of genetic immunization has been acknowledged for almost a decade, but disappointing immunogenicity in humans has delayed its introduction into the clinical arena. To try to increase the potency of genetic immunization, we and others have evaluated 'translocatory' proteins, which are thought to exit living cells by an uncharacterized pathway, and enter neighboring cells in an energy-independent manner. Several laboratories, including our own, have begun to question these remarkable properties. Our previous studies showed that the ability of an epitope to induce major histocompatibility complex (MHC) class I restricted CD8+ T cells was, indeed, enhanced by its being attached to the proposed translocatory sequence of the HIV-1 tat protein. However, we found little evidence that the increased immunogenicity resulted from transfer of the fusion peptide between living cells, and we proposed that it resulted instead from an increased epitope/MHC expression on the surface of transfected cells. Here, we directly test this hypothesis. We show that cells cotransfected with plasmids encoding an epitope, and the relevant MHC class I allele, can stimulate epitope-specific T cells, and that attachment of the epitope to a putative translocatory sequence - which we term herein an 'integral cationic region' (ICR) - leads to a marked increase in stimulatory activity. This elevated stimulatory capacity does not result from a nonspecific increase in MHC class I expression. We use a high-affinity T-cell receptor (TcR) specific for the epitope/MHC combination to quantitate directly the cell-surface expression of the immunogenic complex, and we show that the attachment of the tat ICR to an epitope results in a substantial enhancement of its cell-surface presentation. These data suggest an alternative explanation for the immune enhancement seen with ICRs.

Original languageEnglish (US)
Pages (from-to)2067-2073
Number of pages7
JournalGene therapy
Volume10
Issue number25
DOIs
StatePublished - Dec 1 2003

Fingerprint

Major Histocompatibility Complex
Epitopes
HIV
Immunization
Human Immunodeficiency Virus tat Gene Products
T-Lymphocyte Epitopes
T-Cell Antigen Receptor
HIV-1
Plasmids
Alleles
T-Lymphocytes
Peptides
Proteins

Keywords

  • CD8+ T cell
  • DNA vaccine
  • HIV tat
  • High-affinity TcR
  • Transduction
  • Translocatory proteins

ASJC Scopus subject areas

  • Genetics

Cite this

The cationic region from HIV tat enhances the cell-surface expression of epitope/MHC class I complexes. / Leifert, J. A.; Holler, P. D.; Harkins, S.; Kranz, David M; Whitton, J. L.

In: Gene therapy, Vol. 10, No. 25, 01.12.2003, p. 2067-2073.

Research output: Contribution to journalArticle

Leifert, J. A. ; Holler, P. D. ; Harkins, S. ; Kranz, David M ; Whitton, J. L. / The cationic region from HIV tat enhances the cell-surface expression of epitope/MHC class I complexes. In: Gene therapy. 2003 ; Vol. 10, No. 25. pp. 2067-2073.
@article{4a75cf61089147d48f28fa22ea4ce925,
title = "The cationic region from HIV tat enhances the cell-surface expression of epitope/MHC class I complexes",
abstract = "The potential of genetic immunization has been acknowledged for almost a decade, but disappointing immunogenicity in humans has delayed its introduction into the clinical arena. To try to increase the potency of genetic immunization, we and others have evaluated 'translocatory' proteins, which are thought to exit living cells by an uncharacterized pathway, and enter neighboring cells in an energy-independent manner. Several laboratories, including our own, have begun to question these remarkable properties. Our previous studies showed that the ability of an epitope to induce major histocompatibility complex (MHC) class I restricted CD8+ T cells was, indeed, enhanced by its being attached to the proposed translocatory sequence of the HIV-1 tat protein. However, we found little evidence that the increased immunogenicity resulted from transfer of the fusion peptide between living cells, and we proposed that it resulted instead from an increased epitope/MHC expression on the surface of transfected cells. Here, we directly test this hypothesis. We show that cells cotransfected with plasmids encoding an epitope, and the relevant MHC class I allele, can stimulate epitope-specific T cells, and that attachment of the epitope to a putative translocatory sequence - which we term herein an 'integral cationic region' (ICR) - leads to a marked increase in stimulatory activity. This elevated stimulatory capacity does not result from a nonspecific increase in MHC class I expression. We use a high-affinity T-cell receptor (TcR) specific for the epitope/MHC combination to quantitate directly the cell-surface expression of the immunogenic complex, and we show that the attachment of the tat ICR to an epitope results in a substantial enhancement of its cell-surface presentation. These data suggest an alternative explanation for the immune enhancement seen with ICRs.",
keywords = "CD8+ T cell, DNA vaccine, HIV tat, High-affinity TcR, Transduction, Translocatory proteins",
author = "Leifert, {J. A.} and Holler, {P. D.} and S. Harkins and Kranz, {David M} and Whitton, {J. L.}",
year = "2003",
month = "12",
day = "1",
doi = "10.1038/sj.gt.3302115",
language = "English (US)",
volume = "10",
pages = "2067--2073",
journal = "Gene Therapy",
issn = "0969-7128",
publisher = "Nature Publishing Group",
number = "25",

}

TY - JOUR

T1 - The cationic region from HIV tat enhances the cell-surface expression of epitope/MHC class I complexes

AU - Leifert, J. A.

AU - Holler, P. D.

AU - Harkins, S.

AU - Kranz, David M

AU - Whitton, J. L.

PY - 2003/12/1

Y1 - 2003/12/1

N2 - The potential of genetic immunization has been acknowledged for almost a decade, but disappointing immunogenicity in humans has delayed its introduction into the clinical arena. To try to increase the potency of genetic immunization, we and others have evaluated 'translocatory' proteins, which are thought to exit living cells by an uncharacterized pathway, and enter neighboring cells in an energy-independent manner. Several laboratories, including our own, have begun to question these remarkable properties. Our previous studies showed that the ability of an epitope to induce major histocompatibility complex (MHC) class I restricted CD8+ T cells was, indeed, enhanced by its being attached to the proposed translocatory sequence of the HIV-1 tat protein. However, we found little evidence that the increased immunogenicity resulted from transfer of the fusion peptide between living cells, and we proposed that it resulted instead from an increased epitope/MHC expression on the surface of transfected cells. Here, we directly test this hypothesis. We show that cells cotransfected with plasmids encoding an epitope, and the relevant MHC class I allele, can stimulate epitope-specific T cells, and that attachment of the epitope to a putative translocatory sequence - which we term herein an 'integral cationic region' (ICR) - leads to a marked increase in stimulatory activity. This elevated stimulatory capacity does not result from a nonspecific increase in MHC class I expression. We use a high-affinity T-cell receptor (TcR) specific for the epitope/MHC combination to quantitate directly the cell-surface expression of the immunogenic complex, and we show that the attachment of the tat ICR to an epitope results in a substantial enhancement of its cell-surface presentation. These data suggest an alternative explanation for the immune enhancement seen with ICRs.

AB - The potential of genetic immunization has been acknowledged for almost a decade, but disappointing immunogenicity in humans has delayed its introduction into the clinical arena. To try to increase the potency of genetic immunization, we and others have evaluated 'translocatory' proteins, which are thought to exit living cells by an uncharacterized pathway, and enter neighboring cells in an energy-independent manner. Several laboratories, including our own, have begun to question these remarkable properties. Our previous studies showed that the ability of an epitope to induce major histocompatibility complex (MHC) class I restricted CD8+ T cells was, indeed, enhanced by its being attached to the proposed translocatory sequence of the HIV-1 tat protein. However, we found little evidence that the increased immunogenicity resulted from transfer of the fusion peptide between living cells, and we proposed that it resulted instead from an increased epitope/MHC expression on the surface of transfected cells. Here, we directly test this hypothesis. We show that cells cotransfected with plasmids encoding an epitope, and the relevant MHC class I allele, can stimulate epitope-specific T cells, and that attachment of the epitope to a putative translocatory sequence - which we term herein an 'integral cationic region' (ICR) - leads to a marked increase in stimulatory activity. This elevated stimulatory capacity does not result from a nonspecific increase in MHC class I expression. We use a high-affinity T-cell receptor (TcR) specific for the epitope/MHC combination to quantitate directly the cell-surface expression of the immunogenic complex, and we show that the attachment of the tat ICR to an epitope results in a substantial enhancement of its cell-surface presentation. These data suggest an alternative explanation for the immune enhancement seen with ICRs.

KW - CD8+ T cell

KW - DNA vaccine

KW - HIV tat

KW - High-affinity TcR

KW - Transduction

KW - Translocatory proteins

UR - http://www.scopus.com/inward/record.url?scp=0344465867&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0344465867&partnerID=8YFLogxK

U2 - 10.1038/sj.gt.3302115

DO - 10.1038/sj.gt.3302115

M3 - Article

C2 - 14595379

AN - SCOPUS:0344465867

VL - 10

SP - 2067

EP - 2073

JO - Gene Therapy

JF - Gene Therapy

SN - 0969-7128

IS - 25

ER -