HLA-E–restricted T cells primed by a modified HLA-B*57:01–restricted HIV-1 peptide suppress HIV-1 replication
Hong Sun, Hongbing Yang, Max N. Quastel, Simon Brackenridge, Wanlin He, Anna E. Kliszczak, Margarida Rei, Persephone Borrow, Geraldine M. Gillespie, Andrew J. McMichael
Hong Sun, Hongbing Yang, Max N. Quastel, Simon Brackenridge, Wanlin He, Anna E. Kliszczak, Margarida Rei, Persephone Borrow, Geraldine M. Gillespie, Andrew J. McMichael
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Research Article AIDS/HIV Immunology

HLA-E–restricted T cells primed by a modified HLA-B*57:01–restricted HIV-1 peptide suppress HIV-1 replication

Abstract

HLA-E–restricted HIV-specific T cells offer exciting possibilities for immunotherapy. However, HLA-E binding peptides are rare. A recent study showed that in HLA-B*57:01–positive people with HIV, the peptide that dominates the T cell response, KAFSPEVIPMF (KF11), also stimulates HLA-E–restricted T cells, even though direct binding of this peptide to HLA-E could not be demonstrated. We therefore changed position 2 alanine for methionine in the peptide (referred to as KMF11), which greatly enhanced binding to HLA-E. This enabled the generation of stabilized HLA-E-KMF11 tetramers, which were used to select and then grow specific T cell clones from T cells of HLA-B*57:01–negative blood donors primed with this peptide in vitro. Approximately 20% of these T cell clones reacted with HLA-E–positive cells presenting the native KF11 peptide. Furthermore, these T cells inhibited replication of HIV-1 NL4-3 in CD4+ T cells in vitro. Therefore, this native peptide can be presented by HLA-E to CD8+ T cells, although priming in vivo may depend on cross-reactivities to classical MHC-Ia types. Nevertheless, such T cells could be exploitable for immunotherapy given the conservation of this HIV-1 peptide epitope and the non-polymorphism in HLA-E.

Authors

Hong Sun, Hongbing Yang, Max N. Quastel, Simon Brackenridge, Wanlin He, Anna E. Kliszczak, Margarida Rei, Persephone Borrow, Geraldine M. Gillespie, Andrew J. McMichael

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Figure 3

Functional characterization of HLA-E–restricted CD8+ T cell clones in response to antigen-presenting cells.

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Functional characterization of HLA-E–restricted CD8+ T cell clones in re...
(A) Representative flow cytometry plots of KMF11-primed clone C06, demonstrating cytokine production (TNF-α, IFN-γ), activation (CD137, CD107a/b), and inhibitory marker expression (PD-1, CTLA-4) after coculture with K562E_KF11, K562E_KMF11, and K562E_ECOV2P1 for an incubation period of 10 hours. HLA-E–expressing K562 cells (K562E cells) were included as negative controls. Intracellular cytokine staining of the above markers was performed after surface staining of Live/Dead Fixable Aqua viability dye, and anti-CD3 and anti-CD8 antibodies. Percentages of CD8+ T cells expressing the indicated markers are shown. (B) The expression of CD137, TNF-α, IFN-γ, CD107a/b, PD-1, and CTLA-4 for each CD8 clone in response to KF11-, KMF11-, and ECOV2-expressing K562E cells is shown. For normalization, the background of K562E control was subtracted from each antigen-specific condition. The y axis denotes the percentage of effector marker–positive CD8+ T cells, and the x axis denotes individual CD8+ T cell clones. (C) The expression of CD137, TNF-α, IFN-γ, CD107a/b, PD-1, and CTLA-4 expression in response to KF11-, KMF11-, and ECOV2P1-expressing K562E cells is noted in bar chart format. Friedman’s test was used to test significance. P values are indicated.