CD8+ T Cell Expansion and GVHD Prevention via CD4 Depletion
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Solution Overview
Problem
Current methods for allogeneic hematopoietic cell transplantation (HCT) struggle to effectively expand CD8+ T cells in vivo and prevent both acute and chronic graft-versus-host disease (GVHD) while preserving graft-versus-leukemia (GVL) effects.
Innovation Solution
Administering one or more doses of a therapeutic agent immediately before, during, or after HCT to temporarily deplete CD4+ T cells or reduce serum IL-2, using agents such as anti-CD4 antibodies or anti-IL-2 antibodies, to selectively expand CD8+ T cells in lymphoid tissues and prevent GVHD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If donor CD8+ T cells are used to mediate GVL effects, then leukemia/lymphoma control is improved, but GVHD prevention is worsened because CD8+ T cells can cause GVHD in some contexts
Solution Approach 1:
The patent extracts and removes CD4+ T cells from the allogeneic HCT graft, retaining only CD8+ T cells. This separation allows the GVL effect to be mediated solely by CD8+ T cells while eliminating the GVHD risk associated with CD4+ T cell-mediated immunity. The depletion of CD4+ T cells is achieved through anti-CD4 antibodies or other CD4-specific depleting agents administered before or after HCT.
Solution Approach 2:
The patent applies different functional qualities to different T cell populations: CD8+ T cells are retained for their cytotoxic GVL activity against malignancy, while CD4+ T cells are depleted to remove their pro-inflammatory GVHD activity. This selective retention and removal creates a locally optimized immune profile where only the beneficial GVL function remains.
2Object-affected harmful factors
If CD4+ T cells are depleted to prevent GVHD, then GVHD severity is reduced, but CD8+ T cell expansion and GVL activity may be compromised
Solution Approach 1:
The patent demonstrates that CD8+ T cells can mediate GVL effects independently without requiring CD4+ T cell help. The CD8+ T cells autonomously recognize and eliminate malignant cells through perforin/granzyme mechanisms, making the GVL function self-sufficient and independent of CD4+ T cell presence or absence.
Solution Approach 2:
The patent segments the T cell population into functionally distinct subsets: CD4+ T cells (depleted to remove GVHD risk) and CD8+ T cells (retained for GVL function). This segmentation allows each subset to perform its specialized function without interfering with the other, achieving GVHD prevention while maintaining GVL activity.
3Object-affected harmful factors
If PD-L1 is expressed by recipient tissues to reduce GVHD, then GVHD severity is decreased, but CD8+ T cell expansion in lymphoid tissues is inhibited
Solution Approach 1:
The patent removes the problematic interaction between PD-L1 and CD8+ T cells by depleting CD4+ T cells, which are necessary for maintaining high levels of PD-L1 expression on recipient tissues. Without CD4+ T cell help, PD-L1 expression is reduced, allowing CD8+ T cells to expand effectively in lymphoid tissues while still preventing GVHD through other mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents acute and chronic GVHD by inducing anergy, exhaustion, and apoptosis of CD8+ T cells in GVHD target tissues through PD-L1 interactions, while augmenting CD8+ T cell expansion and GVL effects in lymphoid tissues.
Implementation Method 1
administering one or more doses of a therapeutic agent to a recipient immediately before, during, or immediately after HCT to temporarily deplete CD4+ T cells or to temporarily reduce serum IL-2
Implementation Method 2
PD-L1 interaction with PD-1 induces anergy, exhaustion and apoptosis of activated T cells
Implementation Method 3
PD-L1/CD80 interaction has been reported to inhibit CD28/CTLA4 deficient T cell proliferation in vitro
Implementation Method 4
Proinflammatory cytokines such as IFN-γ augment expression of PD-L1 mRNA and protein by hematopoietic cells, lymphocytes and parenchymal cells
Implementation Method 5
sorted donor CD8+ T cells prevent graft rejection and mediate GVL effects through their expression of perforin/granzyme
Implementation Method 6
flow cytometry-sorted donor CD4+ T cells mediate severe GVHD through expression of FASL and production of proinflammatory cytokines (i.e. IFN-γ and TNF-α)
Implementation Method 7
Th1 and Th17 cells play a critical role in initiating gut GVHD
Data Source
AI summary
Disclosed herein are methods of preventing and treating acute GVHD and chronic GVHD after hematopoietic cell transplantation (HCT), as well as methods of in vivo augmenting expansion of donor CD8+ T cells in the lymphoid tissues in vivo after HCT and methods of augmenting recipient tissue expression of programmed death-ligand 1 (PD-L1, or B7H1) after HCT. The methods entail administering one or more doses of an effective amount of a therapeutic agent to a recipient simultaneously, immediately before, or immediately after HCT to temporarily deplete CD4+ T cells or to reduce serum IL-2. Some examples include an anti-CD4 antibody or an anti-CD4-meditope-immunotoxin, an anti-IL-2 antibody, an agent blocking IL-2R, and/or a PD-L1-Ig. One or more additional therapeutic agents such as IFN-γ can be administered.