Anti-Human F8 Light Chain Monoclonal antibody

VEGF-C is an important mediator of lymphangiogenesis and has been shown to alleviate chronic inflammation in a variety of disease models. In this study, we investigated whether targeted delivery of VEGF-C to sites of inflammation and site-specific activation of lymphatic vessels would represent a clinically feasible strategy for treating chronic skin inflammation. To this end, we generated a fusion protein consisting of human VEGF-C fused to the F8 antibody (F8-VEGF-C), which is specific for the alternatively spliced, angiogenesis-marking extradomain A (EDA) of fibronectin. In two mouse models of psoriasis-like skin inflammation, mediated by transgenic VEGF-A overexpression or repeated application of imiquimod, intravenous treatment with F8-VEGF-C but not with untargeted VEGF-C significantly reduced ear skin edema and was as effective as the clinically used TNF-alpha receptor-Fc fusion protein (TNFR-Fc). Treatment with F8-VEGF-C led to a marked expansion of lymphatic vessels in the inflamed skin and significantly improved lymphatic drainage function. At the same time, treatment with F8-VEGF-C significantly reduced leukocyte numbers, including CD4(+) and gamma delta T cells. In sum, our results reveal that targeted delivery of VEGF-C and site-specific induction of lymphatic vessels represent a potentially new and promising approach for the treatment of chronic inflammatory diseases.

Mice bearing CT26 tumors can be cured by administration of L19-mIL12 or F8-mTNF, two antibody fusion proteins which selectively deliver their cytokine payload to the tumor. In both settings, cancer cures crucially depended on CD8(+) T cells and the AH1 peptide (derived from the gp70 protein of the murine leukemia virus) acted as the main tumor-rejection antigen, with similar to 50% of CD8(+) T cells in the neoplastic mass being AH1-specific after therapy. In order to characterize the clonality of the T cell response, its phenotype, and activation status, we isolated CD8(+) T cells from tumors and secondary lymphoid organs and submitted them to T cell receptor (TCR) and total mRNA sequencing. We found an extremely diverse repertoire of more than 40 000 unique TCR sequences, but the ten most abundant TCRs accounted for >60% of CD8(+) T-cell clones in the tumor. AH1-specific TCRs were consistently found among the most abundant sequences. AH1-specific T cells in the tumor had a tissue-resident memory phenotype. Treatment with L19-mIL12 led to overexpression of IL-12 receptor and of markers of cell activation and proliferation. These data suggest that the antitumor response driven by antibody-cytokine fusions proceeds through an oligoclonal expansion and activation of tumor-infiltrating CD8(+) T cells.