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Modulation of cell-mediated resistance to listeriosis in mice given T-2 toxin
Abstract:
The modulating effect of preinoculation and postinoculation treatment with a single oral 4.0 mg/kg dosage of T-2 toxin on cell-mediated resistance was studied in mice inoculated with Listeria monocytogenes. Toxin treatment caused significant decreases in thymus and spleen weights, bone marrow cellularity, and in the total number of circulating leukocytes, lymphocytes, and neutrophils. Enhancement or suppression of resistance to listeriosis was dependent on the time of toxin administration relative to the time of Listeria challenge. Preinoculation treatment on Day 2 or 4 prior to Listeria challenge significantly enhanced resistance and decreased mortality due to listeriosis by as much as 50%. In contrast, resistance was suppressed and mortality was increased by 50% in mice that were treated with toxin after Listeria challenge. Enhanced resistance to listeriosis was accompanied by a significant increase in the influx of macrophages into Listeria-elicited peritoneal exudates. In addition, in vivo phagocytosis of sheep red blood cells by peritoneal macrophages was significantly increased in toxin-treated mice that were sensitized with sheep erythrocytes. The data indicate that T-2 toxin has a modulating effect on cell-mediated resistance and that enhancement of resistance to listeriosis in mice pretreated with T-2 toxin is associated with increased migration/activation of macrophage effector cells.
Insights
T-2 toxin exposure timing critically impacts immune response to Listeria monocytogenes. Pre-exposure enhances resistance and survival, while post-exposure suppresses immunity, highlighting T-2 toxin
Area of Science:
- Immunology
- Toxicology
- Microbiology
Background:
- Cell-mediated immunity is crucial for controlling intracellular pathogens like Listeria monocytogenes.
- T-2 toxin is a trichothecene mycotoxin known to affect immune cell function.
- Understanding the immunomodulatory effects of T-2 toxin is important for assessing its impact on host defense.
Purpose of the Study:
- To investigate the immunomodulatory effects of T-2 toxin on cell-mediated resistance against Listeria monocytogenes.
- To determine how the timing of T-2 toxin administration influences the host's response to Listeria infection.
Main Methods:
- Mice were inoculated with Listeria monocytogenes and treated with T-2 toxin at different time points (pre- or post-inoculation).
- Assessed parameters included organ weights, leukocyte counts, and survival rates.
- Evaluated macrophage activity through peritoneal exudate cell analysis and in vivo phagocytosis assays.
Main Results:
- T-2 toxin treatment significantly reduced thymus and spleen weights, bone marrow cellularity, and leukocyte counts.
- Pre-treatment with T-2 toxin 2-4 days before Listeria challenge enhanced resistance and reduced mortality by 50%.
- Post-treatment with T-2 toxin suppressed resistance and increased mortality by 50%.
Conclusions:
- T-2 toxin exerts a dose-dependent, time-sensitive modulating effect on cell-mediated immunity.
- Pre-treatment with T-2 toxin enhances resistance to Listeria by increasing macrophage migration and activation.
- Post-treatment with T-2 toxin impairs host defense against Listeria infection.