A Novel Hybrid Multifunctional Cytokine for Immune Reconstitution

描述（由申请人提供）：本提案的目标是开发一种新的杂交双功能细胞因子（“fusokine”），以促进免疫重建并抑制接受造血干细胞移植的癌症患者的移植物抗宿主病（GVHD）。这种fusokine被称为Ha7，由IL-7与肝细胞生长因子(HGF) α链衍生的肽连接而成。为了提高稳定性和延长体内半衰期，每个细胞因子被融合到IgG分子的Fc中，这些分子在哺乳动物细胞表达过程中被修饰以促进异源二聚体的形成。基于IL-7的已知特性，预测Ha7通过刺激T细胞和B细胞淋巴生成以及成熟T细胞的稳态维持来促进免疫重建。在免疫抑制癌症患者同种异体骨髓移植的情况下，HGF片段将增强造血功能，并抑制GVHD。IL-7和HGF联合治疗的另一个好处是保留了免疫抑制癌症患者的胸腺结构和功能。在这个提议中，将产生分泌高水平重组Ha7的稳定细胞系，并纯化fusokine用于功能研究。将在体外研究其对T细胞功能和HGF活性的刺激作用。Ha7将是

DESCRIPTION (provided by applicant): The goal of this proposal is to develop a novel hybrid bifunctional cytokine ("fusokine") to promote immune reconstitution and inhibit graft-versus-host disease (GVHD) in cancer patients undergoing hematopoietic stem cell transplantation. The fusokine, termed Ha7, consists of IL-7 linked to a peptide derived from the alpha chain of hepatocyte growth factor (HGF). To improve stability and extend in vivo half-life each cytokine is fused to the Fc of IgG molecules that were modified to promote the formation of heterodimers during mammalian cell expression. Based on the known properties of IL-7, Ha7 is predicted promote immune reconstitution by stimulating T and B cell lymphopoiesis as well as homeostatic maintenance of mature T cells. The HGF moiety will enhance hematopoiesis, as well as inhibit GVHD in the setting of allogeneic bone marrow transplantation in immunosuppressed cancer patients. Another benefit predicted from the combined treatment with both IL-7 and HGF is the preservation of thymic architecture and function in immunosuppressed cancer patients. In this proposal, stable cell lines secreting high levels of recombinant Ha7 will be produced and the fusokine will be purified for functional studies. Its activity will be studied in vitro for stimulation of T cell functions and HGF activity. Ha7 will be further tested in vivo to evaluate immune reconstitution in immunosuppressed mice given syngeneic bone marrow transplantations (BMT). Ha7 will also be tested in a model of allogeneic BMT in mice that also bear a syngeneic leukemia. In this model, therapeutic efficacy of Ha7 will be demonstrated if it suppresses GVHD while promoting the graft-versus-leukemia effect. This preclinical work will provide the foundation for future development of a novel therapy to restore the immune system and prevent GVHD in cancer patients undergoing stem cell transplantation. PUBLIC HEALTH RELEVANCE: The goal of this project is to develop a novel bifunctional hybrid cytokine for immune reconstitution of cancer patients undergoing stem cell transplantation.