Document Type

Article

Publication Date

5-1-2018

Publication Title

Molecular cancer therapeutics

Keywords

Animals; Cell Line, Tumor; Cytokines; Cytotoxicity, Immunologic; Female; HEK293 Cells; Humans; Immunoglobulin Fc Fragments; Immunoglobulin G; Lymphocyte Activation; Macaca mulatta; OX40 Ligand; Protein Multimerization; Receptors, OX40; Recombinant Fusion Proteins; T-Lymphocytes; T-Lymphocytes, Regulatory

Abstract

Ligation of OX40 (CD134, TNFRSF4) on activated T cells by its natural ligand (OX40L, CD252, TNFSF4) enhances cellular survival, proliferation, and effector functions such as cytokine release and cellular cytotoxicity. We engineered a recombinant human OX40L IgG4P Fc fusion protein termed MEDI6383 that assembles into a hexameric structure and exerts potent agonist activity following engagement of OX40. MEDI6383 displayed solution-phase agonist activity that was enhanced when the fusion protein was clustered by Fc gamma receptors (FcγRs) on the surface of adjacent cells. The resulting costimulation of OX40 on T cells induced NFκB promoter activity in OX40-expressing T cells and induced Th1-type cytokine production, proliferation, and resistance to regulatory T cell (Treg)-mediated suppression. MEDI6383 enhanced the cytolytic activity of tumor-reactive T cells and reduced tumor growth in the context of an alloreactive human T cell:tumor cell admix model in immunocompromised mice. Consistent with the role of OX40 costimulation in the expansion of memory T cells, MEDI6383 administered to healthy nonhuman primates elicited peripheral blood CD4 and CD8 central and effector memory T-cell proliferation as well as B-cell proliferation. Together, these results suggest that OX40 agonism has the potential to enhance antitumor immunity in human malignancies.

Clinical Institute

Cancer

Department

Earle A. Chiles Research Institute

Department

Oncology

Included in

Oncology Commons

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