Antigen recognition during progression from acute to chronic infection with a cagA-positive strain of Helicobacter pylori

Abstract

We have previously published two reports on acute infection with Helicobacter pylori, one of an adult male and one of a family of four. In the present study, we have isolated H. pylori from each of twin boys in the family and compared these by use of random amplified polymorphic DNA PCR. In addition, we have monitored the antibody response over time of the family and the adult male by Western blotting (immunoblotting) with two different strains of H. pylori as the antigen and by use of a commercial kit. The acutely infected twin boys were infected by an identical strain of H. pylori. The twin boys responded to antigens of 19, 26.5, and 29 kDa 30 days after the initial diagnosis, with recognition of 43-to 49-, 66-, 69-, and 87-kDa antigens by day 63. One twin responded to the CagA antigen on day 63, whereas the other responded on day 857. Antibody to the CagA antigen was not detected by use of the infecting strain, UNSW-RU1. Investigation of UNSW-RU1 revealed the presence of cagA. In two acutely infected adults (one, the father of the boys), the initial response to a 45-kDa antigen was later followed by responses to 19-, 29-, 49-, 60-, 77-, and 84-kDa antigens. Sera from the twins' younger sister, born 17 months after the twins acute episode, indicated that she also had become infected. This report supports intrafamilial transmission of H. pylori. Initial antibody responses in the children were to small-molecular-size antigens; in the adults, the initial responses were to larger-molecular-size antigens. The pattern of the serological response differs according to the antigen used. This has implications in regard to international data comparisons.

Problem of Distinguishing False‐Positive Tests from Acute or Transient Helicobacter pylori Infections

“…H. pylori ‐specific IgM antibodies were detectable in some individuals as early as 2 weeks post‐challenge with the majority of individuals having detectable anti‐ H. pylori IgM at 4 weeks post‐challenge. These results were consistent with prior reports [12,13]. IgM antibodies for H. pylori detection are not generally commercially available nor do they have high specificity and sensitivity outside of studies where changes can be assessed from a known baseline.…”

Immunoblot Analysis of Humoral Immune Response to Helicobacter pylori in Children with and without Duodenal Ulcer

“…Younger children may be expected to have infections of short duration and to have more frequently acute primary infections (32,34), showing lower H. pylori serum antibody titers than adults (7). These differences may also be caused by differences in antigen recognition that may occur in different age groups (21,36).…”

Intrafamilial Spread of Helicobacter pylori: A Genetic Analysis

“…Heterozygous DNA was expected to form two mutant/normal heterodublexes showing different migration patterns. Twenty-two cases in total showed mobility shift after Hydrolink analysis (1)(2)(3)(4)(5)7,(9)(10)(11)13,(15)(16)(17)(18)(21)(22)(23)26,28,29,32). Although all of these samples showed mutations in the Urease A gene, the nature of these genetic alterations could not be characterized as we did not proceed to sequence.…”