Inhibition of Melanin From Pseudomonas maltophilia on the Apoptosis Induced by Influenza Virus in MDCK Cells

The situation of apoptosis induced by influenza virus (A1/Jingfang 86 1 and B/Hufang 93 1) in cultured MDCK cells was studied and the selective inhibitory effect of melanin from P.maltophilia on the apoptosis induced by influenza virus was investigated. The results showed that the cytotoxicity of melanin was lower and limit to concentration to MDCK cell line was 100 mg·L -1 . The apoptosis induced activity of influenza virus A1/Jingfang 86 1 strain was more potent than that of B/Hufang 93 1 strain ( p 0.05). In the range of 20~100 mg·L -1 , melanin was found to significantly ( p 0.001) inhibit apoptosis induced by 64 hemagglutinating unit influenza virus. Analysis of the cells by single laser flow cytometry did not show the sub G1 peak (apoptosis peak). Apoptosis index dropped below 3% from 25%~35% by fluorescence microscope detection. From all of these findings, we concluded that melanin form P.meltophilia was able to inhibit apoptosis induced by influenza viru type A and B in MDCK cells.