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Changes in intestinal fluid transport and immune responses to enterotoxins due to concomitant parasitic infection
Abstract:
The effect of a parasitic infection on enterotoxic diarrhea and on local and systemic formation of antibody to the toxin after immunization was studied in mice. Trichinella spiralis infection was chosen as the model, since the effects of the parasite when residing in both intestinal and extraintestinal sites can be studied. It was found that during the intestinal stage of the infection, the fluid response to cholera toxin as well as dibutyryl-cyclic adenosine 3',5' -monophosphate was greatly enhanced and that this was associated with a marked reduction in the absorption of fluid from the intestine. Later in the infection (migration stage), fluid accumulation in response to cholera toxin was significantly reduced, whereas absorption was normal and secretion in response to dibutyryl-cyclic adenosine 3',5'-monophosphate was somewhat increased. Still later in the infection (muscular stage), the fluid-secretory response to cholera toxin was normal. There was a drastic depression of local formation of antitoxin of both immunoglobulin and immunoglobulin classes in mice given the first two of four oral immunizations with cholera toxin during the intestinal stage of T. spiralis infection. When the priming was given before or after the intestinal stage, the local antitoxin response was not affected. The titers of circulating antibodies were also depressed in mice given the first immunizations during the intestinal stage. In addition, significant though less pronounced depression of the serum antibody response was observed in mice primed during the extraintestinal stage.
Insights
Parasitic infections like Trichinella spiralis can disrupt the gut, enhancing diarrhea and significantly reducing antibody formation against toxins. This immune suppression occurs during the intestinal phase of infection.
Area of Science:
- Immunology
- Parasitology
- Gastroenterology
Background:
- Enterotoxic diarrhea remains a significant health concern, often exacerbated by co-infections.
- Understanding the interplay between parasitic infections and host immune responses to bacterial toxins is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the impact of Trichinella spiralis infection on enterotoxic diarrhea.
- To determine how parasitic infection affects local and systemic antibody formation against cholera toxin following immunization.
Main Methods:
- Mice were infected with Trichinella spiralis to model intestinal and extraintestinal parasitic stages.
- The study assessed fluid responses to cholera toxin and dibutyryl cyclic adenosine monophosphate (dbcAMP).
- Local and systemic antibody production (immunoglobulin M and G) against cholera toxin was measured after oral immunization at different infection stages.
Main Results:
- During the intestinal stage of infection, fluid response to cholera toxin and dbcAMP was enhanced, with reduced intestinal fluid absorption.
- Later stages (migration and muscular) showed reduced or normalized fluid responses to cholera toxin.
- Oral immunization during the intestinal parasitic stage drastically reduced local and systemic antibody formation (IgM and IgG) against cholera toxin.
Conclusions:
- Trichinella spiralis infection significantly impairs the host's ability to mount an effective antibody response to cholera toxin, particularly when immunization occurs during the intestinal phase.
- The timing of immunization relative to the parasitic infection stage is critical for successful antibody production.
- These findings highlight the complex immunomodulatory effects of parasitic infections on gut immunity and vaccine efficacy.