Kemampuan Antibodi anti Protease Escherichia coli Enteropatogenik K 1. I dalam Menghambat Kerusakan Sel HEp-2 oleh Protease EPEC

Abstract

Enteropathogenic Escherichia coli (EPEC) K 1.1 is an important cause of severe diarrhea in developing countries, particularly in young infants. This pathogen secreted protease as one of their virulence factor. The aim of this research was to analyze the HEp-2 cells damage due to the EPEC protease, and to analyze the ability of EPEC protease antibodies to reduce the HEp-2 cells damage. Extracellular protease of EPEC was purified by 45% ammonium sulfate precipitation and filtration by milliphore filter $ 0,22 µm. The pure protease was immunized to BALB/c mice five weeks old for seven weeks. After seventh immunization the serum was analyzed by slot blot assay, the serum which consist of antibodies to EPEC protease was harvested after the assay show positive reaction. The positive serum was used to reduce the HEp-2 cells damage due to EPEC protease. From this study we found that HEp-2 cells become damage after the cells were infected with EPEC protease. Cell damage is one expression of the cytotoxic effects. To prove this effects, the viability of the cells were counted using semiquantitative method. This assay showed that viability of the cells decreased more than 50% after the cells incubation with EPEC protease for 9 hour. Antibodies to EPEC protease were used to neutralize the cytotoxic effects on HEp-2 monolayer in vitro. This experiments demonstrated that antibodies to EPEC protease has ability to reduce the HEp-2 cells damage due to EPEC protease.