Elimination of Anti-HLA Alloantibody Producing B Cells through the Use of a CAR-Like HLA Molecule in T Cells

Introduction: T cell immunotherapy using Chimeric Antigen Receptors (CARs) to generate tumor antigen-specific effector T cells has achieved excellent results in anti-leukemic clinical trials, and in a broader appraisal, promising immunotherapeutic results. A major problem in solid organ transplantation is the presence in the recipient of donor specific antibodies, which preclude the success of the transplant due to the associated high risk of antibody-mediated rejection. Methods: we hypothesize that a CAR (chimeric antigen receptor)-like molecule with a particular HLA molecule as the CAR extracellular domain will engineer T cells to kill alloimmune B cells with anti-HLA antibodies as BcR, completely eliminating alloantibodies in a specific manner. Results: first step was to create this chimeric receptor with the HLA-A2 antigen as the CAR-like extracellular domain: extracellular domains of the HLA-A*02:01 molecule were amplified by PCR from cDNA of an A*02:01 positive donor. A CAR comprising the extracellular domains of HLA-A2 and 4-1BB/CD3ζ signalling domain was constructed and delivered by lentiviral transduction into human T cells. The cytotoxic capacity of these transduced T cells was assessed by co-culturing them with EBV-transformed B cells which produce anti-HLA-A2 alloantibodies. Conclusion: specific T cells directed to kill anti-HLA alloantibody producing B cells can be generated by means of the use of an HLA CAR-like receptor. This technology could open new ways of treatment and prevention of antibody-mediated rejection in solid organ transplantation.