Anti-ulcer treatment during pregnancy induces food allergy in mouse mothers and a Th2-bias in their offspring

Abstract

The treatment of dyspeptic disorders with anti-acids leads to an increased risk of sensitization against food allergens. As these drugs are taken by 30-50% of pregnant women due to reflux and heartburn, we aimed here to investigate the impact of maternal therapy with anti-acids on the immune response in the offspring in a murine model. Codfish extract as model allergen was fed with or without sucralfate, an anti-acid drug, to pregnant BALB/c mice during pregnancy and lactation. These mothers developed a codfish-specific allergic response shown as high IgG1 and IgE antibody levels and positive skin tests. In the next step we analyzed whether this maternal sensitization impacts a subsequent sensitization in the offspring. Indeed, in stimulated splenocytes of these offspring we found a relative Th2-dominance, because the Th1- and T-regulatory cytokines were significantly suppressed. Our data provide evidence that the anti-acid drug sucralfate supports sensitization against food in pregnant mice and favors a Th2-milieu in their offspring. From these results we propose that anti-acid treatment during pregnancy could be responsible for the increasing number of sensitizations against food allergens in young infants.

Figure 1

Sucralfate induces sensitization against concomitantly applied codfish proteins. A) Intragastric application (arrows) of codfish extract in context with the antiulcer drug sucralfate (black symbols) to mother mice (n=6 per group) during pregnancy, and lactation leads to increasing codfish-specific IgG1. Control groups of pregnant mice were fed with either PBS (white symbols) or codfish extract alone (gray symbols). The gray area marks the lactation period. Mean values of groups are shown. B) Sucralfate-treatment also induced a positive reaction to codfish in type I skin tests of mother mice (n=6 per group). No reaction to codfish was observed in mothers fed with either PBS or codfish extract alone, respectively to control substances (allergen Bet v 1 from birch pollen or PBS). Substance 48/80 was used as positive control. Representative skin tests of each group are shown.

Figure 2

Codfish-specific maternal IgG1 antibodies are transferred to the offspring. In naive offspring of mother mice treated with sucralfate during pregnancy and lactation, significant amounts of codfish-specific IgG1 could be detected in sera 19 d after birth (black column, n=20). No codfish-specific antibodies were found in the offspring of mothers treated with PBS (white column, n=12) or codfish extract alone (gray column, n=10). Data are representative for two independent experiments and expressed as mean + sd (***P<0.001).

Figure 3

A significant suppression of codfish-specific IgE was found in offspring of sucralfate-treated mice. Offspring were immunized i.p. twice simultaneously with the homologous antigen codfish mixed with the heterologous antigen OVA (arrows). Only in the offspring from sucralfate-treated mothers (black symbols, n=20), the generation of codfish-specific IgE but not OVA-specific IgE was significantly suppressed (B). No influence could be found in the offspring of mice treated with PBS (white symbols, n=12) or codfish extract alone (gray symbols, n=10), or on the levels of codfish- or OVA-specific IgG1 (A) or IgG2a (data not shown). Data are representative for two independent experiments and expressed as mean + se (*P<0.05).

Figure 4

The suppression of codfish-specific IgE was confirmed by β-hexosaminidase release of RBL cells. Sera of offspring before and after two i.p. immunizations (from days 19 and 66 after birth, respectively) were investigated. After passive sensitization of RBL cells with pooled sera of offspring and stimulation with codfish extract, the release of hexosaminidase was much lower in the group where mother mice were treated with sucralfate (black symbols) than in groups of treatment with PBS (white symbols) or codfish (gray symbols). Mean values of triplicates of codfish-induced release of β-hexosaminidase as percentage of total release (after lysis of cells) are shown. Due to the usage of pooled sera statistical analysis could not be performed.

Figure 5

Sensitization of mothers leads to an antigen-independent suppression of IFN-γ and IL-10 production by spleen cells from offspring. Splenocytes of offspring were stimulated with the homologous allergen codfish and the heterologous antigen OVA. A significant suppression of the Th1-cytokine IFN-γ and the T-regulatory cytokine IL-10 in the offspring of mothers treated with codfish plus sucralfate (black columns, n=20) compared with PBS-treated (white columns, n=12) or codfish-treated mothers (gray columns, n=10) was observed. In contrast, no difference was found in the levels of the Th2-cytokine IL-5 (data not shown). Mean values of groups+sd representative for two independent experiments are shown (*P<0.05, **P<0.01, ***P<0.001). The bottom panel indicates that the ratio of the Th2-cytokine IL-5 compared with the suppressed Th1-cytokine IFN-γ was highest in offspring of sucralfate-treated mother mice. This was seen after stimulation of splenocytes with codfish as well as with OVA.