Methods to activate or block the HLA-E/Qa-1 restricted CD8+ T cell regulatory pathway to treat immunological disease

Abstract

Methods are provided for inhibiting or enhancing down-regulation of an antigen-activated HLA-E+ T cell by an HLA-E-restricted CD8+ T cell comprising contacting the HLA-E* T cell and CD8+ T cell with an agent which inhibits or enhances, respectively, binding between (i) T cell receptor (TCR) on the surface of the CD8+ T cell and (ii) a self peptide presented by HLA-E on the surface of the HLA-E+ T cell, thereby inhibiting or enhancing, respectively, down-regulation of the antigen-activated HLA-E+ T cell. Compositions comprising agents which inhibit or enhance / activate, respectively, binding between (i) T cell receptor (TCR) on the surface of a CD8+ T cell and (ii) a self peptide presented by HLA-E on the surface of a HLA-E+ T cell, and assays for identifying such agents, are provided.

Description

[0001]The work disclosed herein was made with government support under grant nos. R29 AI39630; RO1 AI44927; PO1 AI39675; RO1 AI065609; and U19 AI46132 from the National Institutes of Health. Accordingly, the U.S. Government has certain rights in this invention.[0002]Throughout this application, various publications are referenced in parentheses by number. Citations for these references may be found at the end of the specification immediately preceding the claims. The disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains.BACKGROUND[0003]By discriminating self from non-self and controlling the magnitude and class of immune responses, the immune system mounts effective immunity to virtually any foreign antigens but avoids harmful immune responses to self (26 and 27). Immunologically relevant clinical problems often occur due to failure of either proces...

AI Technical Summary

Benefits of technology

[0023]Thus, the novel methods disclosed herein permit control and / or amelioration of autoimmune diseases that can be achieved independent of the knowledge of the particular self-antigens involved in the given autoimmune disease.

[0024]A method is provided for enhancing down-regulation of an antigen-activated HLA-E+ T cell by an HLA-E-restricted or HLA-E-dependent CD8+; T cell comprising contacting the HLA-E+ T cell and CD8+ T cell with an agent which enhances binding between (i) T cell receptor (TCR) on the surface of the CD8+ T cell and (ii) a type B self peptide presented by HLA-E on the surface of the HLA-E+ T cell, thereby enhancing down-regulation of the antigen-activated HLA-E+ T cell.

[0025]A method is provided for enhancing down-regulation of an antigen-activated Qa-1+ T cell by a Qa-1-dependent CD8+ T cell comprising contacting the Qa-1+ T cell and CD8+ T cell with an agent which enhances binding between (i) T cell receptor (TCR) on the surface of the CD8+ T cell and (ii) a type B self peptide presented by Qa-1 on the surface of the Qa-1+ T cell, thereby enhancing down-regulation of the antigen-activated Qa-1+ T cell.

[0026]A method is provided for treating a human subject afflicted with a disorder selected from the group consisting of an autoimmune disease, graft transplant rejection and bacterial infection comprising administering to the subject a therapeutically effective amount of an agent which enhances binding between (i) a T cell receptor (TCR) on the surface of an HLA-E-restricted or HLA-E-dependent CD8+ T cell and (ii) a type B self peptide presented by HLA-E on the surface of an HLA-E+ T cell, thereby treating the subject.

[0032]A method is provided for treating a human subject afflicted with a disorder characterized by excessive CD8+ T cell-mediated immunosuppression comprising administering to the subject a therapeutically effective amount of an agent which inhibits binding between (i) a T cell receptor (TCR) on the surface of an HLA-E-restricted or HLA-E-dependent CD8+ T cell and (ii) a type B self peptide presented by HLA-E on the surface of an HLA-E+ T cell, thereby treating the subject.

Problems solved by technology

Immunologically relevant clinical problems often occur due to failure of either process.

Although the antigen receptors on T or B cells are capable of distinguishing an almost infinite number of distinctive self and foreign antigens, they cannot determine to which antigen they should and to which antigen they should not respond.

As a consequence, the adaptive immune system does not achieve self non-self discrimination by using antigen receptors to recognize the structural differences between self and foreign antigens.

A central issue is how the peripheral immune responses are regulated at a biological system level, which enables the immune system to discriminate self from non-self in order to maintain self-tolerance without damaging its capacity to react to the invasion of foreign pathogens.

In this regard, there is currently no unified conceptual framework to characterize the precise relationship between thymic negative selection and peripheral immune regulation which is the basis for understanding self / non-self discrimination.

The absence of a unified conceptual framework has led to confusion, at both theoretical and experimental levels, in the field of immune regulation.

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