Regulatory T Cell Culture Without CD28 for Stable Foxp3

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Solution Overview

Problem

Existing methods for inducing regulatory T cells from peripheral T cells face challenges with unstable Foxp3 expression due to epigenetic regulation issues, making them unsuitable for clinical applications.

Innovation Solution

A method involving culturing peripheral T cells with CD3 stimulation and the absence of CD28 stimulation, along with TGFβ, IL-2, and optionally ascorbic acid, to induce stable regulatory T cells with demethylated Foxp3 expression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods are used to induce regulatory T cells from peripheral T cells, then regulatory T cells can be generated, but Foxp3 expression becomes unstable

Engineering Contradiction:
ImproveFoxp3 expression stabilityVSAvoidepigenetic regulation of Foxp3
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the culture conditions by removing TGFβ from the culture medium and instead providing TGFβ signaling through engineered cells or modified protocols, which fundamentally alters the epigenetic state and leads to stable Foxp3 expression. This parameter change in the culture system resolves the instability issue.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces an intermediary element - engineered cells or modified culture systems that provide TGFβ signaling without direct addition of TGFβ to the medium. This intermediary approach achieves stable Foxp3 expression while avoiding the problems associated with conventional TGFβ-containing culture methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If TGFβ is added to culture medium to induce regulatory T cells, then differentiation is promoted, but epigenetic demethylation of Foxp3 does not occur

Engineering Contradiction:
Improveregulatory T cell differentiation efficiencyVSAvoidepigenetic demethylation of Foxp3
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention extracts TGFβ from the culture medium while maintaining its essential signaling function through alternative means. By removing TGFβ from the medium but preserving its signaling capability through engineered systems, the invention achieves both differentiation efficiency and proper epigenetic demethylation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary action by pre-engineering cells or establishing modified culture systems that will provide appropriate TGFβ signaling throughout the differentiation process. This preliminary setup ensures that both differentiation and epigenetic demethylation occur correctly from the start of culture.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If existing demethylation methods are used, then general demethylation can be achieved, but regulatory T cell-specific demethylation does not occur

Engineering Contradiction:
Improvedemethylation extentVSAvoidspecificity for regulatory T cell genes
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The invention applies local quality by creating culture conditions that specifically target demethylation at regulatory T cell-specific loci (such as the Foxp3 TSDR region) while leaving other genomic regions unaffected. This localized epigenetic modification achieves the desired specificity for regulatory T cell gene expression.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the cultural parameters and signaling environment to create a specific epigenetic landscape that promotes demethylation only at regulatory T cell-specific genes. By modifying the culture system rather than using general demethylation agents, the invention achieves both extent and specificity of demethylation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3842522B1Method for producing regulatory t cells
Publication Date: 2025.10.15 OSAKA UNIVERSITY
  • EP3842522B1 patent drawingFigure 1
  • EP3842522B1 patent drawingFigure 2
  • EP3842522B1 patent drawingFigure 3

AI summary

Provided is a method for producing regulatory T cells, comprising the step of culturing mammalian-derived peripheral T cells in a medium comprising TGFβ and IL-2 in the presence of CD3 stimulation and in the absence of CD28 stimulation. The medium may further comprise ascorbic acid. The method may further comprise the step of culturing the obtained cell culture in a medium comprising IL-2.