[Fusion and apoptosis of epithelial cells induced by muramidase released protein of Streptococcus suis type 2].

The pathogenic role of muramidase released protein (MRP), a virulence factor of Streptococcus suis type 2 (SS2) is poorly understood. The purified MRP was co-incubated with HEp-2 cells to determine the effect of MRP on epithelial cells. Under light microscope, two principal morphologic changes were observed. Firstly, the cells were fused to form syncytia and a apoptosis followed. Secondly, single cell was also induced to apoptosis at high level as 18%, which was verified by transmission electron microscopy and flow cytometry. It showed that MRP alone was capable of a virulence factor of SS2.