The Cell Killing Activity of Toxin A of Clostridium Difficile
Meng Xiaoqi et al (Lanzhou Institute of Biological Products,Lanzhou 730046)
This paper described the cell killing activity of toxin A of Clostridium difficile on four cell lines which were Vero(Africa green monkey kidney),TPC-1 (human thyroid papillary carcinoma),NIH 3T3 (mouse fibroblast)and NIH 3T3 ras (NIH 3T3 cell transfected with ras oncogene)cell line. The methods to assess the cell killing activity including trypan blue exclusion test,MTS calorimetric assay, membrane damage test and fluorescence micrographs (morphology of cell nuclei)were performed on the four cell lines. The results showed the order of sensitivity of rounding of cells of four cell lines to toxin A as follows: NIH 3T3 ras,TPC-1,Vero,NIH 3T3.However, the order of sensitivity of cell killing activity of four cell lines to toxin A as follows TPC -1,NIH 3T3, Vero,NIH 3T3 ras. The results indicated the cell killing activity of toxin A on the four cell lines are not identified and not related to cell rounding of toxin A. Under the same dose of cell rounding of toxin A,the dose of cell killing activity of toxin A and the time-course of cell death were very different on the four cell lines. TPC-1 cell line is most sensitive to cell killing activity of toxin A. The dates suggest that the toxin A may have potential therapeutic value in the treatment of some cancers.