Faculty Opinions recommendation of Serum angiotensin-1 converting enzyme activity processes a human immunodeficiency virus 1 gp160 peptide for presentation by major histocompatibility complex class I molecules.

2016 ◽  
Author(s):  
Kenneth Bernstein
Keyword(s):  
Human Immunodeficiency Virus ◽  
Enzyme Activity ◽  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Class I ◽  
Complex Class ◽  
Converting Enzyme ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus ◽  
Human Immunodeficiency Virus 1

scholarly journals Serum angiotensin-1 converting enzyme activity processes a human immunodeficiency virus 1 gp160 peptide for presentation by major histocompatibility complex class I molecules.

1992 ◽  
Vol 175 (6) ◽  
pp. 1417-1422 ◽  
Author(s):  
S Kozlowski ◽  
M Corr ◽  
T Takeshita ◽  
L F Boyd ◽  
C D Pendleton ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Major Histocompatibility Complex ◽  
T Cell ◽  
Class I ◽  
Converting Enzyme ◽  
Major Histocompatibility ◽  
Free System ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus ◽  
Human Immunodeficiency Virus 1

T cell stimulation by the human immunodeficiency virus 1 gp160-derived peptide p18 presented by H-2Dd class I major histocompatibility complex molecules in a cell-free system was found to require proteolytic cleavage. This extracellular processing was mediated by peptidases present in fetal calf serum. In vitro processing of p18 resulted in a distinct reverse phase high performance liquid chromatography profile, from which a biologically active product was isolated and sequenced. This peptide processing can be specifically blocked by the angiotensin-1 converting enzyme (ACE) inhibitor captopril, and can occur by exposing p18 to purified ACE. The ability of naturally occurring extracellular proteases to convert inactive peptides to T cell antigens has important implications for understanding cytotoxic T lymphocyte responses in vivo, and for rational peptide vaccine design.

scholarly journals Human Immunodeficiency Virus Nef Induces Rapid Internalization of the T-Cell Coreceptor CD8αβ

2005 ◽  
Vol 79 (17) ◽  
pp. 11422-11433 ◽  
Author(s):  
Veronique Stove ◽  
Inge Van de Walle ◽  
Evelien Naessens ◽  
Elisabeth Coene ◽  
Christophe Stove ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Surface Expression ◽  
Class I ◽  
Complex Class ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus ◽  
Β Chain

ABSTRACT Human immunodeficiency virus (HIV) Nef is a membrane-associated protein decreasing surface expression of CD4, CD28, and major histocompatibility complex class I on infected cells. We report that Nef strongly down-modulates surface expression of the β-chain of the CD8αβ receptor by accelerated endocytosis, while CD8 α-chain expression is less affected. By mutational analysis of the cytoplasmic tail of the CD8 β-chain, an FMK amino acid motif was shown to be critical for Nef-induced endocytosis. Although independent of CD4, endocytosis of the CD8 β-chain was abrogated by the same mutations in Nef that affect CD4 down-regulation, suggesting common molecular interactions. The ability to down-regulate the human CD8 β-chain was conserved in HIV-1, HIV-2, and simian immunodeficiency virus SIVmac239 Nef and required an intact AP-2 complex. The Nef-mediated internalization of receptors, such as CD4, major histocompatibility complex class I, CD28, and CD8αβ, may contribute to the subversion of the host immune system and progression towards AIDS.

scholarly journals Direct Binding of Human Immunodeficiency Virus Type 1 Nef to the Major Histocompatibility Complex Class I (MHC-I) Cytoplasmic Tail Disrupts MHC-I Trafficking

2002 ◽  
Vol 76 (23) ◽  
pp. 12173-12184 ◽  
Author(s):  
Maya Williams ◽  
Jeremiah F. Roeth ◽  
Matthew R. Kasper ◽  
Rebekah I. Fleis ◽  
Chris G. Przybycin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Major Histocompatibility Complex ◽  
Major Histocompatibility Complex Class ◽  
Human Immunodeficiency Virus Type ◽  
Cytoplasmic Tail ◽  
Complex Class ◽  
Mhc I ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus

ABSTRACT Nef, an essential pathogenic determinant for human immunodeficiency virus type 1, has multiple functions that include disruption of major histocompatibility complex class I molecules (MHC-I) and CD4 and CD28 cell surface expression. The effects of Nef on MHC-I have been shown to protect infected cells from cytotoxic T-lymphocyte recognition by downmodulation of a subset of MHC-I (HLA-A and -B). The remaining HLA-C and -E molecules prevent recognition by natural killer (NK) cells, which would otherwise lyse cells expressing small amounts of MHC-I. Specific amino acid residues in the MHC-I cytoplasmic tail confer sensitivity to Nef, but their function is unknown. Here we show that purified Nef binds directly to the HLA-A2 cytoplasmic tail in vitro and that Nef forms complexes with MHC-I that can be isolated from human cells. The interaction between Nef and MHC-I appears to be weak, indicating that it may be transient or stabilized by other factors. Supporting the fact that these molecules interact in vivo, we found that Nef colocalizes with HLA-A2 molecules in a perinuclear distribution inside cells. In addition, we demonstrated that Nef fails to bind the HLA-E tail and also fails to bind HLA-A2 tails with deletions of amino acids necessary for MHC-I downmodulation. These data provide an explanation for differential downmodulation of MHC-I allotypes by Nef. In addition, they provide the first direct evidence indicating that Nef functions as an adaptor molecule able to link MHC-I to cellular trafficking proteins.

scholarly journals Selective Downregulation of Rhesus Macaque and Sooty Mangabey Major Histocompatibility Complex Class I Molecules by Nef Alleles of Simian Immunodeficiency Virus and Human Immunodeficiency Virus Type 2

2008 ◽  
Vol 82 (6) ◽  
pp. 3139-3146 ◽  
Author(s):  
M. Quinn DeGottardi ◽  
Anke Specht ◽  
Benjamin Metcalf ◽  
Amitinder Kaur ◽  
Frank Kirchhoff ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Major Histocompatibility Complex ◽  
Amino Acid ◽  
Major Histocompatibility Complex Class ◽  
Rhesus Macaques ◽  
Complex Class ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus ◽  
Sooty Mangabeys ◽  
Siv Infection

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) Nef downregulates HLA-A and -B molecules, but not HLA-C or -E molecules, based on amino acid differences in their cytoplasmic domains to simultaneously evade cytotoxic T lymphocyte (CTL) and natural killer cell surveillance. Rhesus macaques and sooty mangabeys express orthologues of HLA-A, -B, and -E, but not HLA-C, and many of these molecules have unique amino acid differences in their cytoplasmic tails. We found that these differences also resulted in differential downregulation by primary simian immunodeficiency virus (SIV) SIVsmm/mac and HIV-2 Nef alleles. Thus, selective major histocompatibility complex class I downregulation is a conserved mechanism of immune evasion for pathogenic SIV infection of rhesus macaques and nonpathogenic SIV infection of sooty mangabeys.

scholarly journals Two Human Immunodeficiency Virus Vaccinal Lipopeptides Follow Different Cross-Presentation Pathways in Human Dendritic Cells

2003 ◽  
Vol 77 (2) ◽  
pp. 1564-1570 ◽  
Author(s):  
Muriel Andrieu ◽  
Jean-François Desoutter ◽  
Estelle Loing ◽  
Jésintha Gaston ◽  
Daniel Hanau ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
T Lymphocytes ◽  
Major Histocompatibility Complex Class ◽  
Complex Class ◽  
Cross Presentation ◽  
Histocompatibility Complex ◽  
Immunodeficiency Virus ◽  
Human Dendritic Cells

ABSTRACT An efficient vaccine against human immunodeficiency virus (HIV) must induce good cellular immune responses. To do this, it must be processed and presented by dendritic cells, which are required for primary T-lymphocyte stimulation. We have previously shown that a model lipopeptide containing a short epitopic peptide from HIV-1 was endocytosed and presented in association with major histocompatibility complex class I molecules by human dendritic cells to specific CD8+ T lymphocytes, but the cross-presentation pathway needed to be precisely determined. We have studied a longer lipopeptide (Pol461-484) and another lipopeptide (Nef66-97) currently being used in vaccine trials. Like the shorter lipopeptide, the rhodamine-labeled Pol461-484 lipopeptide was internalized by endocytosis, as assessed by confocal microscopy. The lipopeptides were processed by dendritic cells and presented to CD8+ T cells specific for the HLA-A*0201-restricted Pol476-484 and the HLA-A*0301-restricted Nef73-82 epitope, respectively. Presentation of both lipopeptides was inhibited by brefeldin A. Presentation of the Pol lipopeptide was inhibited by epoxomycin, a proteasome-specific inhibitor, but not by monensin. This shows that it gained access to the cytosol to be digested by the proteasome. In contrast, presentation of the Nef lipopeptide was not inhibited by epoxomycin but was inhibited by monensin, a classical inhibitor of acid-dependent endosomal enzyme activity, indicating an endocytic processing pathway yielding to major histocompatibility complex class I-restricted presentation. Therefore, the two lipopeptides followed different cross-presentation pathways, both resulting in efficient presentation to CD8+ T lymphocytes.

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