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Depression of natural killer activity and mitogen responsiveness in mice treated with pristane
Abstract:
In BALB/c mice, the injection of pristane resulted in a severe decrease in splenic T and B cell proliferative responses to mitogens and in a depression of natural killer (NK) activity. The effects of T and B cells, which persisted for at least 5 mo, were mediated by different mechanisms. T cell responsiveness to PHA dropped significantly below control levels 1 wk after the first of three monthly pristane injections, whereas B cell proliferation in response to LPS did not decrease until 4 wk after the first injection. The removal of plastic-adherent suppressor cells completely restored T cell proliferative capacity, but had no effect on B cells. NK activity against YAC-1 tumor targets was reduced 1 mo after the first pristane injection and remained depressed for at least 3 mo. This depression was not mediated by plastic-adherent suppressor cells. Spleen cell NK activity from pristane-treated mice could not be augmented by the interferon inducer Poly I:C to the same extent as that of control mice. This suggests an effect of pristane on either pre-NK cells or on cells that regulate NK activity.
Insights
Pristane administration severely impairs T and B cell responses and natural killer (NK) cell activity in mice. These immune system effects persist for months and are mediated by distinct mechanisms, impacting immune cell function.
Area of Science:
- Immunology
- Toxicology
Background:
- Pristane is a hydrocarbon known to induce autoimmune conditions in susceptible mouse strains.
- Understanding the immunomodulatory effects of pristane is crucial for studying autoimmune disease pathogenesis.
Purpose of the Study:
- To investigate the impact of pristane on splenic T cell, B cell, and natural killer (NK) cell functions in BALB/c mice.
- To elucidate the mechanisms underlying pristane-induced immune suppression.
Main Methods:
- BALB/c mice were injected with pristane.
- Splenic T and B cell proliferation assays were performed using mitogens (PHA and LPS).
- Natural killer (NK) cell activity was assessed against YAC-1 tumor targets.
- The role of plastic-adherent suppressor cells was evaluated by their removal.
Main Results:
- Pristane significantly decreased T and B cell proliferation and NK cell activity, persisting for at least 3-5 months.
- T cell suppression was reversible by removing plastic-adherent suppressor cells, while B cell suppression was not.
- NK cell activity reduction was not mediated by suppressor cells and showed impaired augmentation by Poly I:C.
Conclusions:
- Pristane induces profound and long-lasting immunosuppression affecting T cells, B cells, and NK cells through different mechanisms.
- Suppressor cells play a role in T cell dysfunction, but not in B cell or NK cell impairment.
- Pristane may affect NK cell development or regulatory pathways, warranting further investigation.