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Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters
Published on: September 27, 2012
Circadian rhythms in surface molecules of rat blood lymphocytes
Carme Pelegrí1, Jordi Vilaplana, Cristina Castellote
1Grup d'Autoimmunitat i Tolerància, Departament de Fisiologia-Divisió IV, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain. cpelegri@farmacia.far.ub.es
Insights
Immune cell counts and surface molecule expression in rats exhibit daily rhythms, influencing immune cell function. This study reveals a temporal organization of immune responses tied to the circadian cycle.
Area of Science:
- Immunology
- Chronobiology
- Hematology
Background:
- Circadian rhythms regulate physiological processes, but their impact on immune cell dynamics is not fully understood.
- Understanding daily variations in immune cell populations and surface molecule expression is crucial for comprehending immune system function.
Purpose of the Study:
- To investigate the circadian rhythmicity of lymphocyte subpopulations and surface molecule expression in rats.
- To analyze daily fluctuations in leukocyte and erythrocyte counts.
- To determine the temporal organization of immune cell markers and their potential role in immune function.
Main Methods:
- Blood samples were collected from rats every 2 hours over a 24-hour period.
- Flow cytometry and monoclonal antibodies were used to analyze lymphocyte surface molecules.
- Analysis included lymphocyte subpopulations, leukocyte differentials, and total red and white blood cell counts.
Main Results:
- The number of B, total T, gamma delta T, T helper, and T cytotoxic/suppressor cells followed a 24-hour rhythm.
- Circadian rhythms were observed in the expression of CD45, CD5, CD3, and CD4 surface molecules.
- Specific temporal associations were found between CD45/CD5 and CD4/CD3 expression patterns.
Conclusions:
- Circadian rhythms significantly influence the number and surface molecule expression of key immune cells in rats.
- The identified temporal organization of immune cells suggests a coordinated daily regulation of immune responses.
- These findings highlight the importance of chronobiology in immune cell function and potential therapeutic strategies.
Abstract:
The present article examines whether the expression of certain surface molecules that trigger immune responses shows a circadian rhythm. We also analyzed the rhythms in the number and percentage of lymphocyte subpopulations, in the leukocyte differential counts, and in the total red and white blood cell counts. Blood samples obtained from rats at 2-h intervals for 24 h were stained with several mouse monoclonal antibodies directed against lymphocyte surface molecules and processed by flow cytometry. The number of B, total T, Tgammadelta, Th, and Ts/c cells followed a 24-h rhythm with a peak in the first half of the resting period. The expression of CD45, CD5, CD3, and CD4 followed a circadian rhythm. Their acrophases suggested temporal association between CD45 and CD5 at the end of the active phase and between CD4 and CD3 at the beginning of this phase. This temporal organization could have an important role for immune cell function.
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