Thioglycollate-elicited murine macrophages are cytotoxic to Mycoplasma arginini-infected YAC-1 tumor cells

Resumo

Macrophages are important components of natural immunity involved in inhibition of tumor growth and destruction of tumor cells. It is known that these cells can be activated for tumoricidal activity by lymphokines and bacterial products. We investigated whether YAC-1 tumor cells infected with Mycoplasma arginini stimulate nitric oxide (NO) release and macrophage cytotoxic activity. Thioglycollate-elic- ited macrophages from male BALB/c mice were co-cultured for 20 h with YAC-1 tumor cells infected or not with Mycoplasma arginini. The cytotoxic activity was evaluated by MTT assay and nitrite levels were determined with the Griess reagent. Thioglycollate-elicited mac- rophages co-cultured with noninfected YAC-1 cells showed low cytotoxic activity (34.7 ± 8.6%) and low production of NO (4.7 ± 3.1 μM NO 2- ). These macrophages co-cultured with mycoplasma-in- fected YAC-1 cells showed significantly higher cytotoxic activity (61.4 ± 9.1%; P<0.05) and higher NO production (48.5 ± 13 μM NO 2- ; P<0.05). Addition of L-NAME (10 mM), an inhibitor of NO synthesis, to these co-cultures reduced the cytotoxic activity to 37.4 ± 2% (P<0.05) and NO production to 3 ± 4 μM NO 2- (P<0.05). The present data show that Mycoplasma arginini is able to induce macro- phage cytotoxic activity and that this activity is partially mediated by NO.

Descrição

Palavras-chave

Macrophages, Cytotoxicity, Mycoplasma, Tumor cells, Nitric oxide

Citação

RIBEIRO-DIAS, F.; RUSSO, M.; NASCIMENTO, F. R. F. ; BARBUTO, J. A. M. ; TIMENETSKY, J.; JANCAR, S . Thioglycollate-elicited murine macrophages are cytotoxic to Mycoplasma arginini-infected YAC-1 tumor cells. Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v. 31, n. 11, p. 1425-1428, Nov. 1998.