title: Generation of recombinant canine interleukin-15 and evaluation of its effects on the proliferation and function of canine NK cells.
abstract: Interleukin-15 (IL-15) is a pleiotropic cytokine that plays a pivotal role in both innate and adaptive immunity. IL-15 is also a promising cytokine for treating cancer. Despite the growing importance of the clinical use of IL-15 for immunotherapy, no attempts have been made to generate a recombinant canine IL-15 (rcIL-15) and to examine its effects on the antitumor activities of immune effector cells in dogs. Here, we generated an rcIL-15 protein consisting of Asn-49-Ser-162 with a C-terminal His tag and examined its functions ex vivo in terms of the proliferation and antitumor effects on canine non-B, non-T, large granular natural killer (NK) cells. Non-B, non-T, large granular NK cells rapidly expanded in response to stimulation with rcIL-15 in the presence of IL-2, and a majority of the cells that selectively expanded over 21 days exhibited a CD3(-)CD5(-)CD4(-)CD8(+/-)CD21(-) phenotype. Purified rcIL-15 significantly enhanced the expansion rate of canine NK cells derived from peripheral blood mononuclear cells compared to human IL-15, or culture in the absence of IL-15 for 21 days (p<0.05). Purified rcIL-15 was superior at enhancing the effector function of NK cells compared to human IL-15. The cytotoxic activity against canine thyroid adenocarcinoma (CTAC) cells, interferon-γ production, and the mRNA expression levels of perforin and granzyme B of expanded NK cells cultured with rcIL-15 were significantly elevated compared to those cultured with human IL-15 or without IL-15 (p<0.05). Intravenous administration of rcIL-15 significantly increased the numbers of lymphocytes in the peripheral blood of dogs on days 6, 8, and 11 after injection compared to numbers before administration (p<0.05). The results of this study suggest that the rcIL-15 protein, consisting of Asn-49-Ser-162, enhanced the proliferation and antitumor effects of canine NK cells and promoted the generation of lymphocytes in dogs.
authors.affiliation: Department of Integrated Life Science and Technology, Kongju National University, Yesan-eup, Yesan-gun, Chungnam 340-702, Republic of Korea; Department of Laboratory and Companion Animal Science, College of Industrial Science, Kongju National University, Yesan-eup, Yesan-gun, Chungnam 340-702, Republic of Korea.
authors.forename: Soo-Hyeon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Laboratory and Companion Animal Science, College of Industrial Science, Kongju National University, Yesan-eup, Yesan-gun, Chungnam 340-702, Republic of Korea. Electronic address: shin-phd@daum.net.
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Shin
authors.affiliation: Department of Integrated Life Science and Technology, Kongju National University, Yesan-eup, Yesan-gun, Chungnam 340-702, Republic of Korea; Department of Laboratory and Companion Animal Science, College of Industrial Science, Kongju National University, Yesan-eup, Yesan-gun, Chungnam 340-702, Republic of Korea. Electronic address: sangki@kongju.ac.kr.
authors.forename: Sang-Ki
authors.initials: SK
authors.lastname: Kim
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000662:veterinary; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004285:Dogs; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis; D019409:Interleukin-15 / Q000138:chemical synthesis / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D007958:Leukocyte Count / Q000662:veterinary; D008297:Male; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000662:veterinary
chemical_list: D019409:Interleukin-15; D011994:Recombinant Proteins; D007371:Interferon-gamma
keywords: Canine; Immunotherapy; Interleukin-15; NK cells; Recombinant protein