Analysis of Helicobacter pylori isolates from Chile: occurrence of selective type 1 Lewis b antigen expression in lipopolysaccharide

Abstract

Previous studies have shown that the LPS of Helicobacter pylori isolated from North American and European hosts predominantly expresses type 2 Lewis x (Lex) and Ley epitopes, whilst the LPS from Asian strains has the capacity to express type 1 Lea and Leb structures. The aim of this study was to evaluate the expression of Le antigens and the cytotoxin-associated antigen (CagA) by H. pylori isolates from Chile. A total of 38 isolates were screened. The expression of Le antigens and CagA was determined by whole-cell indirect ELISA, using commercially available monoclonal anti-Le and polyclonal anti-CagA antibodies. LPS profiles of H. pylori isolates were assessed by gel electrophoresis and Western blotting. Expression of Lex and/or Ley epitopes was confirmed in 32/38 isolates (84 %), whilst 9/38 isolates (24 %) expressed type 1 Leb blood group determinants, in addition to type 2 Lex and Ley structures. Six strains (16 %) were non-typeable. The majority of H. pylori strains examined were CagA-positive (83.3 %).

Actividad antibacteriana in vitro de propóleos chilenos sobre Helicobacter pylori

“…pylori coloniza la mucosa gástrica de más de la mitad de la población mundial y es responsable de gastritis crónica, úlcera péptica, adenocarcinoma y linfoma asociado a la mucosa gástrica 7,10 . El tratamiento convencional sólo logra entre 70 y 80% de éxito en la cura de los pacientes, por lo que se busca activamente alternativas terapéuticas distintas a los antimicrobianos, como vacunas, probióticos, inactivación fotodinámica, fagoterapia y búsqueda de productos fitoterapéuticos o nutracéuticos [8][9][10][13][14][15][16] .…”

“…Helicobacter pylori es una bacteria que coloniza la mucosa gástrica y se relaciona con gastritis crónica, úlcera gastro-duodenal y cáncer gástrico. La infección por H. pylori constituye una infección crónica extensamente difundida en la especie humana, afectando alrededor de 50% de la población mundial 7,8 . La erradicación de la infección por H. pylori contempla la administración de fármacos inhibidores de la bomba de protones asociado al uso combinado de dos antimicrobianos; los más usados son claritromicina más amoxicilina o metronidazol.…”

Helicobacter pylori isolates from Greek children express type 2 and type 1 Lewis and α1,6-glucan antigens in conjunction with a functional type IV secretion system

“…Co-expression of a1,6-glucan with Le x and/or Le y antigens in the majority of H. pylori strains examined suggests the importance of this LPS component in the pathogenesis of H. pylori. We have previously shown that a1,6-glucan affects the colonizing ability of H. pylori and is required for initial colonization of the murine stomach (Altman et al, 2008). In this context, the presence of a1,6-glucan in H. pylori strains isolated from children could be considered another important phenotypic characteristic facilitating successful colonization and contributing to the antigenic diversity of H. pylori LPS.…”

“…Following centrifugation (5000 g, 5 min, 4 uC), pellets were suspended in 25 ml PBS to give a final concentration of 10 8 cells ml 21 . WCE was performed as previously described (Altman et al, 2008). Briefly, the wells of a microtitre plate were coated with 100 ml bacterial suspension (10 8 cells ml 21 ) overnight at 4 uC.…”

“…The corresponding secondary antibody HRP-anti-mouse IgG+IgM diluted 1 : 3000 in 10 mM PBS was added, and the nitrocellulose membranes were incubated for 1 h at room temperature. The membranes were washed three times with 10 mM PBS between the incubation steps and developed as described previously (Altman et al, 2008) using SuperSignal West Pico Chemiluminescent substrate (Pierce), following the manufacturer's instructions.…”