JlpA, a novel surface‐exposed lipoprotein specific to Campylobacter jejuni, mediates adherence to host epithelial cells

Abstract

A 1116 bp open reading frame (ORF), designated jlpA, encoding a novel species-specific lipoprotein of Campylobacter jejuni TGH9011, was identified from recombinant plasmid pHIP-O. The jlpA gene encodes a polypeptide (JlpA) of 372 amino acid residues with a molecular mass of 42.3 kDa. JlpA contains a typical signal peptide and lipoprotein processing site at the N-terminus. The presence of a lipid moiety on the JlpA molecule was confirmed by the incorporation of [3H]-palmitic acid. Immunoblotting analysis of cell surface extracts prepared using glycine-acid buffer (pH 2.2) and proteinase K digestion of whole cells indicated that JlpA is a surface-exposed lipoprotein in C. jejuni. JlpA is loosely associated with the cell surface, as it is easily extracted from the C. jejuni outer membrane by detergents, such as sarcosyl and Triton X-100. JlpA is released to the culture medium, and its concentration increases in a time-dependent fashion. The adherence of both insertion and deletion mutants of jlpA to HEp-2 epithelial cells was reduced compared with that of parental C. jejuni TGH9011. Adherence of C. jejuni to HEp-2 cells was inhibited in a dose-dependent manner when the bacterium was preincubated with anti-GST-JlpA antibodies or when HEp-2 cells were preincubated with JlpA protein. A ligand-binding immunoblotting assay showed that JlpA binds to HEp-2 cells, which suggests that JlpA is C. jejuni adhesin.

Involvement of Lipoprotein NlpI in the Virulence of Adherent Invasive Escherichia coli Strain LF82 Isolated from a Patient with Crohn's Disease

“…Such a role has been reported for the surface-exposed lipoprotein JlpA expressed by Campylobacter jejuni (16). NlpI is supposed to be targeted to the outer membrane in the E. coli cell envelope (M. Ohara, personal communication).…”

“…Finally, bacterial lipoproteins are also involved in adhesion to and invasion of epithelial cells (42). For example, the surface-exposed lipoprotein JlpA specific to Campylobacter jejuni mediates adherence to HEp-2 epithelial cells and Lsp, which belongs to the LraI lipoprotein family, is involved in Streptococcus pyogenes adhesion to and invasion of A549 cells (11,16).…”

Molecular mechanisms and biological role ofCampylobacter jejuniattachment to host cells

“…JlpA is a lipoprotein involved in adhesion [23]. This protein, which is loosely associated with the outer membrane, is able to bind heat shock protein 90 on the surface of HEp-2 epithelial host cells, leading to the activation of NF-κB and p38 MAP kinase [20,23].…”

“…This protein, which is loosely associated with the outer membrane, is able to bind heat shock protein 90 on the surface of HEp-2 epithelial host cells, leading to the activation of NF-κB and p38 MAP kinase [20,23]. Mutations in jlpA gene resulted in reduced adherence of JlpA to HEp-2 epithelial cells [23].…”

“…Mutations in jlpA gene resulted in reduced adherence of JlpA to HEp-2 epithelial cells [23]. Purified JlpA inhibited adherence of C. jejuni to HEp-2 cells confirming the role of the former as an adhesin [23]. However, inactivation of jlpA gene did not affect the ability of C. jejuni to bind to chicken LMH cells or to colonise broiler chickens [17], and also did not reduce attachment to human T84 human colonic adenocarcinoma cell [24] suggesting that only certain host cells are able to produce receptors for this adhesin.…”