Conversion of anti-tissue factor antibody sequences to chimeric antigen receptor and bi- specific T cell engager format

Abstract Background The efficacy of antibody-targeted therapy of solid cancers is limited by the lack of consistent tumour-associated antigen expression. However, tumour associated antigens shared with non-malignant cells may still be targeted using conditionally activated-antibodies or by chimeric antigen receptor (CAR) T cells or CAR NK cells activated either by the tumour microenvironment or following 'unlocking' via multiple antigen-recognition. In this study we have focused on tissue factor (TF; CD142), a type I membrane protein present on a range of solid tumours as a basis for future development of conditionally-activated BiTE or CAR T cells. TF is frequently upregulated on multiple solid tumours providing a selective advantage for growth, immune evasion and metastasis, as well as contributing to the pathology of thrombosis via the extrinsic coagulation pathway. Methods Two well-characterised anti-TF monoclonal antibodies hATR-5 and TF8-5G9 maintained their nanomolar affinities following conversion into a single chain (scFv) format. maintained their nanomolar affinities following conversion into a single chain (scFv) format.CD28-CD3-based CAR or CD3-based BiTE format based on the anti-TF mAb scFv constructs were able to activate T cells. Two well-characterised anti-TF monoclonal antibodies hATR-5 and TF8-5G9 maintained their nanomolar affinities following conversion into a single chain (scFv) format. CD28-CD3-based CAR or CD3-based BiTE format based on the anti-TF mAb scFv constructs were able to activate T cells. Conclusion Because of the broad expression of TF on a range of solid cancers, anti-TF antibody formats provide a useful addition for the development of conditionally activated biologics for antibody and cellular-based therapy.