title: Immune modulation by interleukin-12 in tumor-bearing mice receiving vitamin D3 treatments to block induction of immunosuppressive granulocyte/macrophage progenitor cells.
abstract: Lewis lung carcinoma (LLC-LN7) tumors stimulate myelopoiesis and increase the presence of granulocyte/macrophage (GM) progenitor cells having natural suppressor activity. Treatment of these tumor-bearing mice with interleukin-12 (IL-12) resulted in minimal immune modulation. The objective of this study was to determine whether eliminating natural suppressor activity would allow for immune stimulation by IL-12. Treatment of LLC-LN7 tumor-bearing mice with vitamin D3 eliminated natural suppressor activity. In mice that were first treated with vitamin D3 and then also with IL-12, there was stimulation of splenic T cell proliferation in response to immobilized anti-CD3 plus IL-2. In addition, spleen and lymph node cells from vitamin-D3/IL-12-treated tumor-bearing mice became stimulated in response to autologous tumor to produce interferon gamma (IFN gamma), although IL-2 production was not stimulated. A prominent effect of the combined vitamin-D3/IL-12 treatment regimen was the synergistic augmentation of autologous tumor-specific cytolytic activity within the regional lymph nodes. The generation of these tumor-specific effector cells required the presence of the tumor mass since such activity was not elicited in the lymph nodes of mice from which the tumors had been surgically excised. The results of this study show that, after treatment of tumor bearers with vitamin D3 to eliminate GM-suppressor cells, IL-12 can induce select regional antitumor immune responses, particularly IFN gamma production and cytolysis by regional lymph node cells of autologous tumor.
authors.affiliation: Research Service, Hines VA Hospital, IL 60141, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Prechel
authors.forename: Y
authors.initials: Y
authors.lastname: Lozano
authors.forename: M A
authors.initials: MA
authors.lastname: Wright
authors.forename: J
authors.initials: J
authors.lastname: Ihm
authors.forename: M R
authors.initials: MR
authors.lastname: Young
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000276:immunology* / Q000628:therapy; D002455:Cell Division / Q000187:drug effects; D002762:Cholecalciferol / Q000494:pharmacology*; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D007108:Immune Tolerance / Q000187:drug effects*; D007167:Immunotherapy; D007371:Interferon-gamma / Q000378:metabolism; D018664:Interleukin-12 / Q000494:pharmacology*; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D018664:Interleukin-12; D002762:Cholecalciferol; D007371:Interferon-gamma