Partial characterization of an external polysaccharide of Helicobacter pylori by using an immunoglobulin M monoclonal antibody

Abstract

A monoclonal immunoglobulin M antibody, HP15/36, was produced by a hybridoma cell line prepared by fusion of mouse myeloma cell line Sp2/O with spleen cells of mice immunized with Helicobacter pylori D273 (French strain). Immunoelectron microscopy of whole bacteria and ultrathin sections showed that the determinant was located outside the bacterial cell, possibly in the outermost areas. This external reactivity was observed by immunofluorescence and immunoperoxidase assays and was confirmed by immunogold study at the ultrastructural level. The reactive epitope was formol and picric acid resistant and allowed the detection of the bacterium on fixed tissue biopsy specimens. The reactive component was extracted with phenol-water. Immunoblotting with such an antigen exhibited a clearly positive reactivity at a molecular mass between 50 and 120 kDa. This reactivity was suppressed by periodate oxidation, suggesting a carbohydrate epitope. The diagnostic value and significance of this polysaccharide in microbe-host interactions remain to be determined.

Mucoid Helicobacter pylori Isolates with Fast Growth under Microaerobic and Aerobic Conditions

“…Production of EXP by H. pylori in vivo might also play important roles in protection of the bacterium against stomach acid [10,20] and in the bacterial resistance to the specific and nonspecific host defense mechanisms [21]. Specific monoclonal antibody was used to demonstrate the production of EXP both in vitro and in patients [22]. The EXPs produced by Gram‐positive and Gram‐negative bacteria have important roles in the bacterial adhesion and colonization, e.g., in biofilm formation.…”

Biofilm formation byHelicobacter pylori

“…Bacteria that are surrounded by a large quantity of extracellular material will have some protection from fluctuations in pH ( Roberts 1996). Drouet et al . (1993) reported that H. pylori grown on starch‐containing media produced mucoid colonies and also used a specific monoclonal antibody to provide evidence of production of an extracellular polysaccharide both in vitro and in patients.…”

Cell surface characteristics of Helicobacter pylori

“…Nevertheless, the possibility that the reactive component is LPS-related cannot as yet be discounted. In particular, both LPS and this carbohydrate-based antigen can be extracted by phenol-water and both can be lost upon subculturing [11,12,14,54]. The LPS of H. pylon' possesses Osidechains of homogenous chain length (see above) which in SDS-PAGE migrate with an electrophoretic mobility similar to that observed for the carbohydrate-based antigen [11,54].…”

“…In particular, both LPS and this carbohydrate-based antigen can be extracted by phenol-water and both can be lost upon subculturing [11,12,14,54]. The LPS of H. pylon' possesses Osidechains of homogenous chain length (see above) which in SDS-PAGE migrate with an electrophoretic mobility similar to that observed for the carbohydrate-based antigen [11,54]. Furthermore, the 0-sidechains project from the cell surface and can be stained with tannic acid like the glycocalyx of Drouet et al [54].…”