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Effect of ammonium metavanadate on the murine immune response
Abstract:
Female B6C3F1 mice were exposed to ammonium metavanadate (NH4VO3) by intraperitoneal injection every 3 d at 2.5, 5.0, or 10 mg V/kg for 3, 6, or 9 w and were then assayed for alterations in immunoresponsiveness. Resistance to Escherichia coli endotoxin lethality increased in a dose-dependent manner up to 6 w of exposure, while resistance to viable gram-positive Listeria lethality was depressed in a dose-dependent manner. Comparison of LD20 values indicated a 250-fold decrease in resistance to Listeria at the lowest vanadium exposure and a 40% increase in resistance to endotoxin after the highest vanadium exposure. Peritoneal macrophage phagocytic capacities were decreased in a dose-dependent manner, but viabilities remained unaffected. Rosetting capacity of splenic lymphocytes was increased following vanadium exposure. Liver and splenic enlargement was observed, and examination of splenic tissue indicated enhanced formation of megakaryocytes and red blood cell precursors. Subchronic exposure to vanadium may thus disrupt the normal function of the immune system.
Insights
Subchronic exposure to ammonium metavanadate (NH4VO3) altered immune responses in mice. Vanadium exposure increased resistance to endotoxin lethality but decreased resistance to Listeria, impacting macrophage function and splenic tissue.
Area of Science:
- Toxicology
- Immunology
- Hematology
Background:
- Vanadium compounds are industrial chemicals with potential toxicological effects.
- Understanding the impact of subchronic vanadium exposure on the immune system is crucial for risk assessment.
Purpose of the Study:
- To investigate the effects of ammonium metavanadate (NH4VO3) exposure on the immunoresponsiveness of female B6C3F1 mice.
- To determine dose- and time-dependent alterations in immune cell function and resistance to bacterial infections.
Main Methods:
- Mice were exposed to NH4VO3 via intraperitoneal injection at varying doses (2.5, 5.0, 10 mg V/kg) and durations (3, 6, 9 weeks).
- Immune responses were assessed by measuring resistance to Escherichia coli endotoxin and Listeria monocytogenes lethality.
- Peritoneal macrophage phagocytosis, splenic lymphocyte rosetting capacity, and splenic tissue morphology were analyzed.
Main Results:
- Ammonium metavanadate exposure increased resistance to endotoxin lethality in a dose-dependent manner (up to 40% increase).
- Conversely, resistance to Listeria lethality decreased significantly (up to 250-fold decrease at lowest dose).
- Macrophage phagocytic capacity was reduced, while splenic lymphocyte rosetting capacity increased. Liver and spleen enlargement, along with enhanced megakaryocyte and red blood cell precursor formation, were observed.
Conclusions:
- Subchronic exposure to ammonium metavanadate disrupts normal immune system function in mice.
- Vanadium exposure leads to differential effects on resistance to gram-negative and gram-positive bacterial challenges.
- These findings highlight the immunomodulatory and hematotoxic potential of vanadium compounds.