[Establishment and evaluation of array-ELISA for detection of enterotoxins from Staphylococcus aureus].

Objective To accurately and rapidly detect and type five classical Staphylococcal enterotoxins (SEs) by array-ELISA using a combination of a chip and ELISA. Methods SEs were prepared by prokaryotic expression and affinity chromatography. Hybridoma cells were injected intraperitoneally into mice to prepare ascites. A monoclonal antibody was obtained by ascites purification. The sensitivity and specificity of the antibody were evaluated by ELISA. The antibody was printed in one cell, and the sensitivity and specificity of array-ELISA were evaluated. Results Except for the detection limit of Staphylococcal enterotoxin C (SEC) being 10 ng/mL, 0.0001 ng/mL SEs could be detected by array-ELISA in PBS. The detection limit was 0.001-10 ng/mL for SEs in milk. The specificity was 100% in both PBS and milk. No cross reaction was observed between SEs. Additionally, no cross reaction was observed between SEB and botulinum toxin. Conclusion Array-ELISA has been successfully established, and it can simultaneously detect and discriminate five classical SEs within one sample sensitively and specifically.

Pseudomonas aeruginosa mannose-sensitive hemagglutinin inhibits proliferation and invasion via the PTEN/AKT pathway in HeLa cells.

We investigated the effects of Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) on the proliferation and invasion of human cervical cancer cell lines, as well as the molecular pathways underlying these effects. MTT cell proliferation assays revealed a time- and concentration-dependent cytotoxic effect of PA-MSHA on HeLa cells but not H8 cells. Flow cytometry with propidium iodide and annexin-V-fluorescein isothiocyanate labeling (FITC) indicated that various concentrations of PA-MSHA could induce apoptosis and G2-M cell cycle arrest in HeLa cells. PA-MSHA also impaired the migration and invasion abilities of HeLa cells in Wound healing and Transwell invasion assays. Western blot results demonstrated that PA-MSHA reduced the expression of p-AKT, p-GSK3ß, BCL-2, Vimentin and ß-catenin, but increased the levels of PTEN, BAD, BAX and E-cadherin in HeLa cells. Importantly, PTEN siRNA induced the activity of p-AKT, while PA-MSHA partly inhibited this induction, indicating that PA-MSHA may reduce the cell proliferation and invasion potential by activating PTEN and thus inhibiting the AKT pathway in vitro. These data suggest the potential application of PA-MSHA to the treatment of human cervical cancer.