Modeling and predicting stress-induced immunosuppression in mice using blood parameters

Area of Science:

• Immunotoxicology
• Stress Physiology
• Biomarker Discovery

Background:

• Corticosterone AUC models stress effects on spleen and thymus immunity.
• Blood immune cell data is crucial for human risk assessment.
• Previous studies lacked blood-based immune response data under known stressor AUCs.

Purpose of the Study:

• To assess immune parameter changes in mouse blood correlating with known corticosterone AUC values.
• To determine if blood immune markers can predict stressor effects similarly to spleen markers.
• To evaluate MHC II expression as a reliable blood biomarker for stress exposure.

Main Methods:

• Mice were treated with exogenous corticosterone, restraint, propanil, atrazine, or ethanol.
• Peripheral blood immune cells were analyzed via flow cytometry (MHC II, B220, CD4, CD8).
• Leukocyte counts, differential counts, spleen cell number, and NK cell activity were assessed.

Main Results:

• MHC II expression in blood showed consistent quantitative relationships with corticosterone AUC.
• Blood immune parameters exhibited greater variability compared to spleen parameters.
• Chemical stressors did not replicate restraint stress effects in blood leukocytes as observed in the spleen.

Conclusions:

• MHC II expression in mouse blood is a reasonably consistent indicator of stress exposure, mirroring spleen findings.
• Blood immune cell analysis, particularly MHC II, can contribute to risk assessment parallelograms.
• While variability exists, blood immune markers offer valuable insights into stressor impacts.