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 4

KMF11-specific HLA-E–restricted CD8+ T cells lyse antigen-expressing K562E cells.

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KMF11-specific HLA-E–restricted CD8+ T cells lyse antigen-expressing K56...
(A) K562E_KMF11 SCT cells (CellTrace CFSE-labeled) were mixed with control K562E cells and K562E_Mtb44 SCT–expressing cells at 1:1:1. These cells were cocultured with cloned KMF11-specific HLA-E–restricted CD8+ T cells for 48 hours at E/T ratios as shown, in duplicate. Flow plots of clone C26 and a control clone are shown, gating on viable CD3–CD8– cells, quantifying K562E_KMF11 target cells remaining, boxed in red. (B) Percentage of CFSE-positive K562E_KMF11 SCT cells after coculture with KMF11-specific CD8+ T cell clones (red symbols) or 2 irrelevant ECOV2 CD8+ T cell clones (gray dots) at E/T 1:1 and 5:1. (C) Reduction of KMF11 SCT–expressing cells by KMF11-specific, HLA-E–restricted CD8+ T cells, using the formula [1 – (% target cells with specific T clone/% target cells with irrelevant control T clone)] × 100 at E/T ratio of 5:1 compared with 1:1. Significance assessed using Wilcoxon’s signed-rank test. *P < 0.05. Each clone is denoted using different symbols. Two independent experiments were performed. (D) CellTrace CFSE–labeled K562E_KF11 SCT cells were mixed with K562E cells and then cocultured with KMF11-specific HLA-E–restricted CD8+ T cells for 48 hours, in duplicate, at E/T ratios shown. The percentage of K562_KF11 cells remaining is boxed in red. (E) The percentages of CFSE-positive K562E_KF11 SCT–expressing cells after coculture with KMF11-specific CD8+ T cell clones (red symbols) or 2 irrelevant ECOV2 CD8+ T cell clones (gray dots). (F) Increasing E/T ratios of 1:1 to 5:1 and 20:1 enhanced lysis of K562E-KF11 cells. Significance determined by 1-way ANOVA with Tukey’s multiple-comparison test. *P < 0.05, **P < 0.01. (G) Time-dependent inhibition of K562E_KF11–expressing cells by CD8+ T cell clones. Two irrelevant T cell clones were negative controls. Significance tested by 1-way ANOVA with Tukey’s multiple-comparison test. ***P = 0.0001, ****P < 0.0001. Two independent experiments were performed.