Regulatory T cells but not NKT I cells are modulated by a single low-dose cyclophosphamide in a B cell lymphoma tumor-model.

MJ RICO; VR ROZADOS; LE MAINETTI; MF ZACARÍAS FLUCK; P MATAR ; O. G SCHAROVSKY

Experimental Oncology

Kyiv : Morion

Año: 2012 vol. 34 p. 38 - 42

1812-9269

Experimental and clinical studies showed that the administration of cyclophosphamide (Cy) in low doses leads to an enhancementof the antitumor immune response. Our objective was to study the modulation, if any, by low dose Cy, of T regulatory (Treg) and naturalkiller T (NKT) I cells, two cell populations of the innate immune response with opposing effects on the tumors, in a rat B cell lymphomamodel. Methods: Inbred e rats were challenged s.c. with L-TACB lymphoma and on day 14 animals were distributed in two groups.Treated: injected i.p. with cyclophosphamide (10mg/kg of body weight) and Control: injected i.p. with saline. Blood samples were takenfrom days 0 to 21 and the percentage of T regulatory and natural killer T I cells were determined by flow cytometry. Results: We foundthat the increase of natural and inducible T regulatory cells of peripheral blood achieved during tumor growth was significantly downregulatedby cyclophosphamide. On the contrary, natural killer T I cells were not modulated by the treatment. Conclusion: The antimetastaticeffect of a single low dose of Cy would be due, at least in part, to downregulation of natural and inducible T regulatory cells.Key Words: T regulatory cells, NKT I cells, cyclophosphamide, lymphoma.