Therapeutic in situ CAR T cells in genetically humanized HLA DQ8 mouse models 4607

Abstract Description Antigen receptor (CAR) T cells can be generated in vivo within the natural lymph node (LN) environment as the immune response to a virus infection unfolds. This in situ approach entails priming LNs with intradermal inoculations of replication defective adenoviruses encoding MHC class I and class II allo/xeno-antigens. Universal transplant antigens were devised for LN priming by introducing tryptophan into amino acid position 162 of the MHC HLA-A2:01 class I heavy chain and by using the mouse MHC class II beta chain to form chimeric class II antigens with endogenous class II alleles. The virus encoded mismatched MHC antigen presenting molecules are expressed functionally in the LN following intradermal inoculation provoking polyclonal T cells responses. Three days later CAR T cells are generated by directly injecting retroviruses encoding CARs of interest into the responding LN. Mouse CD19-specifc CAR T cells created in this manner in B6-DQ8 and DQ8/A2 mice effectively target endogenous B cells and are therapeutic in male and female Emu-myc lymphomas demonstrating the potential for the generating functional CAR T cells directly in vivo. While in situ CAR T cells are readily produced in B6, B6-IA0/DQ8, B6-IA0/DQ8/A2, and B6-IA0/DQ6 LNs, functional differences among the strains emerged in the periphery suggesting that properties of the autoimmune-associated HLA DQ8 class II allele is particularly reactive during the production of CAR T cells in vivo. Funding Sources MustangBio, Inc Mayo Clinic Center of Biomedical Research Mayo Clinic Department of Immunology Mayo Clinic Graduate School of Biomedical Science Fraternal Order of Eagles Mayo Clinic Ventures NIH R21 AI 097337 NIH R01 CA 178804 NIH T32 AI 07425 Topic Categories Tumor Immunology: Checkpoints, Prevention, and Treatment (TIPT)