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Relationship between enhanced macrophage phagocytic activity and the induction of interferon by Newcastle disease
Abstract:
The relationship between phagocytic activity of peritoneal macrophages and serum interferon (IF) titers was evaluated in mice challenged with Newcastle disease virus (NDV). Time course studies indicated peak serum IF titers between 6 and 12 hr, whereas Fc receptor-mediated macrophage phagocytosis was maximal 18 hr after viral administration. Both responses decreased in parallel as the inoculated dose of the virus was reduced. Splenectomy, shown by others to decrease the NDV-induced serum IF titers, significantly decreased the stimulation of phagocytosis. The role of T cells in the response to the virus was studied with nude mice raised under germfree conditions. NDV-induced serum IF titers and macrophage phagocytosis were both diminished in BALB/c nudes compared with their heterozygous littermates. Both responses could be partially restored by transfer of thymocytes obtained from heterozygous mice. The results provide further evidence that in vivo macrophage stimulation by NDV is mediated by induced IF. The experiments with nude mice also indicate that the IF response to NDV is regulated by T lymphocytes.
Insights
Newcastle disease virus (NDV) stimulates peritoneal macrophage phagocytosis via induced interferon (IF). T lymphocytes regulate this interferon response, crucial for macrophage activity against NDV infection.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Peritoneal macrophages play a key role in innate immunity.
- Interferon (IF) is a critical cytokine in antiviral responses.
- Newcastle disease virus (NDV) is a significant avian pathogen.
Purpose of the Study:
- To investigate the relationship between serum interferon (IF) titers and peritoneal macrophage phagocytic activity following Newcastle disease virus (NDV) challenge in mice.
- To elucidate the role of T lymphocytes and splenectomy in the NDV-induced immune response, specifically focusing on interferon production and macrophage function.
Main Methods:
- Mice were challenged with NDV, and time course studies were performed to measure serum IF titers and Fc receptor-mediated macrophage phagocytosis.
- The effects of splenectomy on IF titers and phagocytosis were assessed.
- Experiments using germfree BALB/c nude mice and thymocyte transfer were conducted to evaluate the role of T cells.
Main Results:
- Peak serum IF titers occurred 6-12 hours post-NDV administration, while maximal macrophage phagocytosis was observed at 18 hours.
- Both IF titers and phagocytosis decreased with reduced viral dose and were significantly diminished by splenectomy.
- NDV-induced IF and phagocytosis were reduced in nude mice compared to heterozygotes, with partial restoration upon thymocyte transfer.
Conclusions:
- In vivo macrophage stimulation by NDV is mediated by induced interferon (IF).
- The interferon response to NDV is regulated by T lymphocytes, highlighting their importance in adaptive immunity against viral infections.