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HLA-Cw*0102-restricted HIV-1 p24 epitope variants can modulate the binding of the inhibitory KIR2DL2 receptor and primary NK cell function.

ABSTRACT: Accumulating evidence suggests an important role for Natural Killer (NK) cells in the control of HIV-1 infection. Recently, it was shown that NK cell-mediated immune pressure can result in the selection of HIV-1 escape mutations. A potential mechanism for this NK cell escape is the selection of HLA class I-presented HIV-1 epitopes that allow for the engagement of inhibitory killer cell immunoglobulin-like receptors (KIRs), notably KIR2DL2. We therefore investigated the consequences of sequence variations within HLA-Cw*0102-restricted epitopes on the interaction of HLA-Cw*0102 with KIR2DL2 using a large panel of overlapping HIV-1 p24 Gag peptides. 217 decameric peptides spanning the HIV-1 p24 Gag consensus sequence were screened for HLA-Cw*0102 stabilization by co-incubation with Cw*0102?/TAP-deficient T2 cells using a flow cytometry-based assay. KIR2DL2 binding was assessed using a KIR2DL2-IgG fusion construct. Function of KIR2DL2? NK cells was flow cytometrically analyzed by measuring degranulation of primary NK cells after co-incubation with peptide-pulsed T2 cells. We identified 11 peptides stabilizing HLA-Cw*0102 on the surface of T2 cells. However, only one peptide (p24 Gag??????? AAEWDRLHPV) allowed for binding of KIR2DL2. Notably, functional analysis showed a significant inhibition of KIR2DL2? NK cells in the presence of p24 Gag???????-pulsed T2 cells, while degranulation of KIR2DL2? NK cells was not affected. Moreover, we demonstrated that sequence variations in position 7 of this epitope observed frequently in naturally occurring HIV-1 sequences can modulate binding to KIR2DL2. Our results show that the majority of HIV-1 p24 Gag peptides stabilizing HLA-Cw*0102 do not allow for binding of KIR2DL2, but identified one HLA-Cw*0102-presented peptide (p24 Gag???????) that was recognized by the inhibitory NK cell receptor KIR2DL2 leading to functional inhibition of KIR2DL2-expressing NK cells. Engagement of KIR2DL2 might protect virus-infected cells from NK cell-mediated lysis and selections of sequence polymorphisms that increase avidity to KIR2DL2 might provide a mechanism for HIV-1 to escape NK cell-mediated immune pressure.

SUBMITTER: Fadda L

PROVIDER: S-EPMC3395618 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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HLA-Cw*0102-restricted HIV-1 p24 epitope variants can modulate the binding of the inhibitory KIR2DL2 receptor and primary NK cell function.

Fadda Lena L Körner Christian C Kumar Swati S van Teijlingen Nienke H NH Piechocka-Trocha Alicja A Carrington Mary M Altfeld Marcus M

PLoS pathogens 20120712 7

Accumulating evidence suggests an important role for Natural Killer (NK) cells in the control of HIV-1 infection. Recently, it was shown that NK cell-mediated immune pressure can result in the selection of HIV-1 escape mutations. A potential mechanism for this NK cell escape is the selection of HLA class I-presented HIV-1 epitopes that allow for the engagement of inhibitory killer cell immunoglobulin-like receptors (KIRs), notably KIR2DL2. We therefore investigated the consequences of sequence v ...[more]

PMID: 22807681

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Project description:BackgroundCD8+ T cell-mediated adaptive cellular immunity and natural killer (NK) cell-mediated innate immunity both play important roles in tumour immunity. This study aimed to develop therapeutic tumour vaccines based on double-activation of CD8+ T and NK cells.MethodsThe immune Epitope database, Molecular Operating Environment software, and enzyme-linked immunosorbent assay were used for epitope identification. Flow cytometry, confocal microscopy, UPLC-QTOF-MS, and RNA-seq were utilized for evaluating immunity of PBMC-derived DCs, CD8+ T or NK cells and related pathways. HLA-A2.1 transgenic mice combined with immunologically reconstituted tumour-bearing mice were used to examine the antitumour effect and safety of epitope vaccines.ResultsWe identified novel HLA-A2.1-restricted extracellular matrix protein 1(ECM1)-derived immunodominant epitopes in which LA induced a potent immune response. We also found that LA-loaded DCs upregulated the frequency of CD3+/CD8+ T cells, CD45RO+/CD69+ activated memory T cells, and CD3-/CD16+/CD56+ NK cells. We demonstrated cytotoxic granule release of LA/DC-CTLs or LA/DC-NK cells and cytotoxicity against tumour cells and microtissue blocks via the predominant IFN-γ/perforin/granzyme B cell death pathway. Further investigating the mechanism of LA-mediated CD8+ T activation, we found that LA could be internalized into DCs through phagocytosis and then formed a LA-MHC-I complex presented onto the DC surface for recognition of the T cell receptor to upregulate Zap70 phosphorylation levels to further activate CD8+ T cells by DC-CTL interactions. In addition, LA-mediated DC-NK crosstalk through stimulation of the TLR4-p38 MAPK pathway increased MICA/B expression on DCs to interact with NKG2D for NK activation. Promisingly, LA could activate CD8+ T cells and NK cells simultaneously via interacting with DCs to suppress tumours in vivo. Moreover, the safety of LA was confirmed.ConclusionsLA-induced immune antitumour activity through DC cross-activation with CD8+ T and NK cells, which demonstrated proof-of-concept evidence for the capability and safety of a novel therapeutic tumour vaccine.

Dataset Information

HLA-Cw*0102-restricted HIV-1 p24 epitope variants can modulate the binding of the inhibitory KIR2DL2 receptor and primary NK cell function.

Publications

HLA-Cw*0102-restricted HIV-1 p24 epitope variants can modulate the binding of the inhibitory KIR2DL2 receptor and primary NK cell function.

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