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Suppression of natural killer cell activity by Friend murine leukemia virus
Abstract:
BALB/c mice infected with Friend murine leukemia virus (F-MuLV) evinced a decreased natural killer (NK) cell activity to susceptible target cells. This suppression increased as the interval between infection and assay was lengthened. The decrease in NK activity due to F-MuLV infection was partially reversible when spleen cells were pretreated with interferon before the cytolytic assay. The ability of F-MuLV-infected splenocytes to bind to target cells was unaltered, indicating that the defect was in the lytic phase of NK cytolysis. When mixed with uninfected spleen cells, F-MuLV-infected splenocytes suppressed their NK cell activity. This suppression was associated with a nylon wool-adherent cell population in the F-MuLV-infected spleens.
Insights
Friend murine leukemia virus (F-MuLV) infection in mice impairs natural killer (NK) cell activity, with suppression worsening over time. This NK cell defect is linked to specific spleen cells and partially reversed by interferon treatment.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Friend murine leukemia virus (F-MuLV) is known to affect the immune system.
- Natural killer (NK) cells are crucial for innate immunity against viral infections and tumors.
- Understanding NK cell dysfunction during viral infections is vital for developing therapeutic strategies.
Purpose of the Study:
- To investigate the impact of F-MuLV infection on NK cell activity in BALB/c mice.
- To determine the phase of NK cell-mediated cytotoxicity affected by F-MuLV.
- To explore potential mechanisms and reversibility of NK cell suppression.
Main Methods:
- BALB/c mice were infected with F-MuLV.
- Natural killer cell activity was assessed using susceptible target cells at various time points post-infection.
- Spleen cells were treated with interferon prior to cytolytic assays.
- Cell binding assays were performed to evaluate target cell interaction.
- Co-culture experiments with infected and uninfected splenocytes were conducted.
Main Results:
- F-MuLV infection led to a progressive decrease in NK cell activity against target cells.
- The defect in NK cell activity was localized to the lytic phase, not the binding phase.
- Interferon pretreatment partially restored NK cell cytotoxic function.
- F-MuLV-infected splenocytes suppressed NK activity of uninfected spleen cells.
- This suppressive effect was associated with nylon wool-adherent cells in infected spleens.
Conclusions:
- F-MuLV infection significantly impairs NK cell-mediated cytotoxicity in a time-dependent manner.
- The primary defect lies in the effector phase of NK cell killing.
- Interferon shows partial efficacy in reversing NK cell suppression.
- A specific spleen cell population in F-MuLV-infected mice mediates NK cell suppression.