CD137 (4-1BB) Costimulation Modifies DNA Methylation in CD8⁺ T Cell-Relevant Genes

Area of Science:

• Immunology
• Epigenetics
• Cancer Immunotherapy

Background:

• CD137 (4-1BB) costimulation influences T cell behavior.
• Epigenetic modifications, like DNA methylation, can mediate long-term cellular changes.
• Understanding these mechanisms is key for optimizing T cell-based cancer therapies.

Purpose of the Study:

• To investigate the long-term epigenetic consequences of CD137 costimulation on human CD8+ T cells.
• To identify specific genes and regulatory factors affected by CD137-induced DNA methylation.
• To explore the role of these epigenetic changes in T cell function and response.

Main Methods:

• Genome-wide DNA methylation arrays on human CD8+ T cells stimulated with CD137 agonist antibodies (e.g., urelumab).
• Confirmation of methylation patterns using pyrosequencing in healthy donors.
• Analysis of mRNA and protein expression for regulated genes, including immune-related genes and transcription factors.

Main Results:

• CD137 costimulation led to consistent DNA methylation patterns in CD8+ T cells.
• Several immune-related genes (CD96, HHLA2, CCR5, CXCR5, CCL5) showed differential methylation and altered expression.
• Epigenetic regulation of transcription factor TCF1 and microRNA miR-21 was observed.
• Methylation patterns differed between naïve and antigen-experienced CD8+ T cells.

Conclusions:

• CD137 costimulation induces genome-wide DNA methylation and chromatin reprogramming in T cells.
• These epigenetic changes likely poise T cells for altered responses upon subsequent antigen recognition.
• CD137 signaling connects T cell priming to lasting epigenetic modifications, impacting immune cell behavior.