title: An antibody fusion protein for cancer immunotherapy mimicking IL-15 trans-presentation at the tumor site.
abstract: Cytokines driving the immune response are powerful tools for cancer immunotherapy, but their application is generally limited by severe systemic toxicity. Targeted approaches by means of antibody-cytokine fusion proteins might enable focus on the cytokine activity to the tumor site, thereby reducing unwanted side effects. Here, we investigated the possibility to improve the efficiency of interleukin (IL)-15 presentation in a targeted approach by the incorporation of an IL-15Rα chain fragment, mimicking physiologic trans-presentation. Therefore, an antibody cytokine fusion protein (scFv_RD_IL-15) composed of an antibody moiety targeting the tumor stromal fibroblast activation protein (FAP), an extended IL-15Rαsushi domain (RD) and IL-15 was generated, exhibiting antibody-mediated specific binding and cytokine activity in soluble and targeted form. Comparative analysis with a corresponding antibody fusion protein devoid of RD (scFv_IL-15) showed for scFv_RD_IL-15 in solution enhanced stimulatory activity on Mo7e (IL-15Rβγ) cells and reduced proliferation response on CTLL-2 (IL-15Rαβγ) cells, while in FAP-targeted, that is, membrane-bound form, comparable proliferation of CTLL-2 (IL-15Rαβγ) cells was obtained. In addition, scFv_RD_IL-15 achieved in its soluble and target-bound form stronger proliferation and cytotoxicity on unstimulated and activated T cells, respectively. Furthermore, in vivo analysis in a lung metastasis tumor mouse model revealed a superior antitumor effect for scFv_RD_IL-15 in comparison with that obtained by an untargeted or RD missing version of IL-15 fusion protein. Thus, tumor-directed trans-presentation of IL-15 in association with RD in form of an antibody fusion protein seems to be a promising approach to further improve the antitumor effect of IL-15.
authors.affiliation: Institut für Zellbiologie und Immunologie, Universität Stuttgart, Stuttgart, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Kermer
authors.forename: Volker
authors.initials: V
authors.lastname: Baum
authors.forename: Nora
authors.initials: N
authors.lastname: Hornig
authors.forename: Roland E
authors.initials: RE
authors.lastname: Kontermann
authors.forename: Dafne
authors.initials: D
authors.lastname: Müller
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D010450:Endopeptidases; D018093:Gelatinases / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007167:Immunotherapy; D019409:Interleukin-15 / Q000276:immunology* / Q000378:metabolism; D053720:Interleukin-15 Receptor alpha Subunit / Q000235:genetics* / Q000378:metabolism; D008175:Lung Neoplasms / Q000276:immunology / Q000517:prevention & control / Q000556:secondary; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018716:Molecular Mimicry; D058990:Molecular Targeted Therapy; D009368:Neoplasm Transplantation; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology*; D012697:Serine Endopeptidases / Q000276:immunology / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000235:genetics*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D000099167:Fibroblast Activation Protein Alpha
chemical_list: D000970:Antineoplastic Agents; D010450:Endopeptidases; D018093:Gelatinases; D019409:Interleukin-15; D053720:Interleukin-15 Receptor alpha Subunit; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D057127:Single-Chain Antibodies; D000099167:Fibroblast Activation Protein Alpha