Targeting B cell leukemia with highly specific allogeneic T cells with a public recognition motif

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Allogeneic T cells offer therapeutic potential for leukemia by leveraging diverse T cell repertoires.
• Tumor-specific T cells are often deleted in patients, necessitating alternative strategies for immune targeting.
• Major histocompatibility complex (MHC)-mismatched donors provide naive T cells not subject to self-antigen deletion.

Purpose of the Study:

• To investigate the potential of allogeneic T cells to target leukemia.
• To identify and characterize T cells recognizing allogeneic human leukocyte antigen (HLA)/peptide complexes.
• To assess the specificity and efficacy of these T cells against leukemia cells.

Main Methods:

• Coculturing HLA-A(*)0201-negative T cells with engineered dendritic cells presenting HLA-A(*)0201/CD20p complex.
• Isolation and characterization of HLA-A(*)0201/CD20p pentamer-reactive CD8(+) T cells.
• Analysis of T cell receptor (TCR) sequences and assessment of killing activity against leukemia cells.

Main Results:

• Polyclonal CD8(+) T cells recognizing the allogeneic HLA-A(*)0201/CD20p complex were successfully generated.
• These T cells demonstrated specific recognition of the target peptide and MHC complex.
• Efficient killing of HLA-A(*)0201-positive B cells, including primary chronic lymphocytic leukemia cells, was observed.
• A novel conservation pattern in TCR sequences, particularly the TCR β chain complementarity-determining region 3, was identified.

Conclusions:

• This study demonstrates the first public recognition motif for an allogeneic HLA/peptide complex.
• Allo-restricted T cells or TCRs can mediate graft-versus-leukemia effects.
• This approach holds promise for leukemia therapy, potentially avoiding graft-versus-host disease.