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Effects of microwave exposure on the hamster immune system. II. Peritoneal macrophage function
Abstract:
Acute exposure to hamsters to microwave energy (2.45 GHz; 25 mW/cm2 for 60 min) resulted in activation of peritoneal macrophages that were significantly more viricidal to vaccinia virus as compared to sham-exposed or normal (minimum-handling) controls. Macrophages from microwave-exposed hamsters became activated as early as 6 h after exposure and remained activated for up to 12 days. The activation of macrophages by microwave exposure paralleled the macrophage activation after vaccinia virus immunization. Activated macrophages from vaccinia-immunized hamsters did not differ in their viricidal activity when the hamsters were microwave- or sham-exposed. Exposure for 60 min at 15 mW/cm2 did not activate the macrophages while 40 mW/cm2 exposure was harmful to some hamsters. Average maximum core temperatures in the exposed (25 mW/cm2) and sham groups were 40.5 degrees C (+/- 0.35 SD) and 38.4 degrees C (+/- 0.5 SD), respectively. In vitro heating of macrophages to 40.5 degrees C was not as effective as in vivo microwave exposure in activating macrophages to the viricidal state. Macrophages from normal, sham-exposed, and microwave-exposed hamsters were not morphologically different, and they all phagocytosed India ink particles. Moreover, immune macrophage cytotoxicity for virus-infected or noninfected target cells was not suppressed in the microwave-irradiated group (25 mW/cm2, 1 h) as compared to sham-exposed controls, indicating that peritoneal macrophages were not functionally suppressed or injured by microwave hyperthermia.
Insights
Microwave energy exposure activates hamster peritoneal macrophages, enhancing their ability to fight vaccinia virus. This microwave-induced immune activation is comparable to that seen after viral immunization.
Area of Science:
- Electromagnetic fields
- Immunology
- Cell biology
Background:
- Peritoneal macrophages play a crucial role in the innate immune response.
- Understanding non-thermal effects of microwave energy on immune cells is important.
Purpose of the Study:
- To investigate the effects of acute microwave energy exposure on peritoneal macrophage activity in hamsters.
- To compare microwave-induced macrophage activation with immune responses to vaccinia virus.
Main Methods:
- Hamsters were exposed to 2.45 GHz microwave energy (25 mW/cm2 for 60 min).
- Macrophage viricidal activity against vaccinia virus was assessed.
- Macrophage morphology and phagocytic capacity were evaluated.
- Core body temperature was monitored.
Main Results:
- Microwave exposure significantly enhanced macrophage viricidal activity against vaccinia virus.
- Macrophage activation was observed as early as 6 hours and persisted for up to 12 days post-exposure.
- In vitro heating to the same temperature was less effective than in vivo microwave exposure.
- No morphological differences or suppression of phagocytosis or cytotoxicity was observed.
Conclusions:
- Acute microwave energy exposure can activate peritoneal macrophages, enhancing their antiviral properties.
- This activation is comparable to that induced by vaccinia virus immunization.
- Microwave hyperthermia at the tested parameters does not appear to suppress overall macrophage function.