Serum antibody responses to the N-acetylneuraminyllactose-binding hemagglutinin of Campylobacter pylori

Abstract

We recently reported that Campylobacter pylori possesses a surface-associated fibrillar hemagglutinin which has an affinity for N-acetylneuraminyllactose; this hemagglutinin may function as a colonization factor for attachment to the gastric epithelium. In the present study we examined serum samples obtained from 65 C. pylon-infected individuals with gastric ulcers, duodenal ulcers, or both and from 121 asymptomatic volunteers, including 62 who were infected with C. pyloni, for immunoglobulin G (IgG) specific for the C. pylori neuramin-lactose-binding hemagglutinin (NLBH). The NLBH purified from a single isolate was used as the antigen in an enzyme-linked immunosorbent assay. A positive result was obtained with serum from 81.5% (53 of 65) of the individuals with ulcers, 67.7% (42 of 62) of the C. pyloni-infected volunteers, and 1.7% (1 of 59) of the C. pylon-negative volunteers. This result confirms that NLBH is produced in vivo. There are several possible explanations for the fact that only 75% of 127 C. pylori-infected individuals were positive for anti-NLBH IgG in serum. We favor the hypothesis that there are probably several antigenically distinct C. pylori NLBHs, i.e., NLBHs which would stimulate antibody that was undetectable by the antigen used in the enzyme-linked immunosorbent assay described here.

Cell surface characteristics of Helicobacter pylori

“…A fibrillar 20 kDa haemagglutinin with specificity for N-acetylneuraminyl-cu(2-3)lactose has been identified and cloned [33,34]. This fibrillar haemagglutinin is expressed in vivo since 81.5% of individuals with ulcers produce antibodies against the polypeptide [35]. Although Huang et al 1361 reported another H. pylon' haemagglutinin of 25 kDa with identical receptor binding, it is possible that these are identical haemagglutinins and that variations in size result from interlaboratory calibration.…”

Flow cytometric analysis of the localization of Helicobacter pylori antigens during different growth phases

“…Studies by Bode et al [5] indicate that the urease is secreted by the bacteria and then reassociated to the bacterial surface. However, using FCM analyses we have shown that neither UreA nor UreB is exposed on the cell surface during any stage of growth, not even when the majority of the cells were coccoids.…”

“…Like urease, the N-acetyl-neuraminyllactose-binding hemagglutinin, HpaA (H. pylori adhesin A), is a conserved protein in H. pylori. HpaA is a 30-kDa protein which has been reported to mediate binding to sialic acid in vitro [5] and to be either a £agellar sheath [6,7], a cytoplasmic [8], or an outer membrane protein of H. pylori [9]. Another H. pylori protein also believed to play a role in pathogenesis is the neutrophil activating protein (NAP).…”

Recombinant HpaA purified from Escherichia coli has biological properties similar to those of native Helicobacter pylori HpaA

“…First, the HpaA protein is highly conserved among H. pylori isolates, being found in all strains analysed so far (7, 8). Secondly, it is immunogenic in humans (9, 10), and thirdly, it is associated with the outer surface of the bacteria (11–14). Furthermore, the protein shows no significant sequence homologies with other known proteins (15, 16) and it is produced during different growth phases in vitro (14).…”