Targeting SLP76:ITK interaction separates GVHD from GVL in allo-HSCT

Area of Science:

• Immunology
• Hematology
• Oncology

Background:

• Allogeneic hematopoietic stem cell transplantation (allo-HSCT) offers a cure for hematological malignancies by leveraging graft-versus-leukemia (GVL) mediated by donor T cells.
• Graft-versus-host disease (GVHD), a major complication of allo-HSCT, is also driven by these same alloreactive T cells.
• Separating the beneficial GVL response from the detrimental GVHD is a critical therapeutic challenge.

Purpose of the Study:

• To investigate the role of the T cell receptor (TCR)-mediated SLP76:ITK interaction in modulating GVL and GVHD.
• To explore the therapeutic potential of inhibiting the SLP76:ITK pathway to selectively enhance GVL while mitigating GVHD.

Main Methods:

• Utilized a mouse model with a Y145F mutation in SLP-76 to assess T cell function in vivo.
• Developed a novel peptide inhibitor targeting the SLP76:ITK interaction.
• Evaluated cytokine production, cellular migration, and anti-leukemia/GVHD activity in both murine and human T cells.

Main Results:

• Mice receiving T cells with the SLP76 Y145F mutation exhibited preserved GVL effects against B-cell acute lymphoblastic leukemia (B-ALL) without inducing GVHD.
• SLP76Y145FKI T cells demonstrated reduced inflammatory cytokine production and migration to GVHD target organs.
• The novel peptide inhibitor decreased PLCγ1 and ERK phosphorylation, reduced cytokine production in human T cells, and effectively separated GVHD from GVL effects.

Conclusions:

• Inhibiting the SLP76:ITK interaction represents a promising strategy to disentangle GVL from GVHD after allo-HSCT.
• This targeted approach holds potential for improving the safety and efficacy of allo-HSCT for hematological malignancies.
• Further development of SLP76:ITK inhibitors could lead to novel immunotherapies for cancer treatment.