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Updated: May 28, 2026
Isolation and Activation of Murine Lymphocytes
Published on: October 30, 2016
A timetable of 24-hour patterns for human lymphocyte subpopulations
G Mazzoccoli1, R B Sothern, A De Cata
1Department of Internal Medicine and Chronobiology Unit, Scientific Institute and Regional General Hospital Casa Sollievo della Sofferenza, S. Giovanni Rotondo, Foggia, Italy. g.mazzoccoli@tin.it
Insights
Immune cell function shows daily rhythms, with specific lymphocyte surface molecules peaking at different times. This molecular timetable highlights the circadian organization of cellular immunity, aiding medical procedures.
Area of Science:
- Immunology
- Chronobiology
- Cell Biology
Background:
- Specific lymphocyte cell surface molecules are crucial for immune responses.
- These molecules exhibit varying circadian patterns, indicating time-dependent immune cell function.
- Understanding these rhythms is key to comprehending immune system regulation.
Purpose of the Study:
- To investigate the daily variation in expression of cytotoxic lymphocyte cell surface molecules.
- To identify circadian rhythms in various lymphocyte subpopulations and antigen receptors.
- To explore the physiological significance of these temporal changes in immune function.
Main Methods:
- Blood samples were collected every 4 hours over 24 hours from 11 healthy men.
- Expression of lymphocyte cell surface clusters of differentiation (CD) and antigen receptors were analyzed.
- Serum melatonin and cortisol levels were measured to confirm circadian synchronization.
Main Results:
- Significant circadian rhythms were observed in six of 10 lymphocyte subpopulations.
- Midday peaks were noted for CD8+dim, gamma-delta TCR, CD8+, and CD16+ cells.
- Nighttime peaks were observed for CD4+ and CD3+ cells, with a late evening peak for CD20+ B cells.
Conclusions:
- Lymphocyte surface molecules display distinct nyctohemeral (daily) changes, revealing a circadian organization of cellular immunity.
- This temporal organization is likely significant for triggering and regulating immune responses.
- The identified molecular timetable can guide medical sampling for experimental, diagnostic, and therapeutic purposes.
Abstract:
Specific lymphocyte cell surface molecules involved in antigen recognition and cell activation present different circadian patterns, with peaks and troughs reflecting a specific time-related compartment of immune cell function. In order to study the dynamics of variation in expression of cytotoxic lymphocyte cell surface molecules that trigger immune responses, several lymphocyte cell surface clusters of differentiation (CD) and antigen receptors, analyses were performed on blood samples collected every 4 h for 24 h from eleven clinically-healthy men. Assays for serum melatonin (peaking at night) and cortisol (peaking near awakening) confirmed 24-h synchronization of the subjects to the light-dark schedule. A significant (p≤0.05) circadian rhythm could be demonstrated for six of the 10 lymphocyte subpopulations, with midday peaks for CD8+dim (T cytotoxic cells, 11:15 h), gammadeltaTCR (gamma-delta T cell receptor-expressing cells, 11:33 h), CD8+ (T suppressor/cytotoxic cells, 12:08 h), and for CD16+ (natural killer cells, 12:59 h), and peaks during the night for CD4+ (T helper/inducer cells, 01:23 h) and CD3+ (total T cells, 02:58 h). A borderline significant rhythm (p = 0.056) was also observed for CD20+ (total B cells), with a peak late in the evening (23:06 h). Acrophases for 3 subsets, CD8+bright (T suppressor cells, 15:22 h), HLA-DR+ (B cells and activated T cells, 23:06 h) and CD25+ (activated T lymphocytes with expression of the alpha chain of IL2 receptor, 23:35 h), where a 24-h rhythm could not be definitively determined, nevertheless provide information on the location of their highest values and possible physiological significance. Thus, specific lymphocyte surface molecules present distinctly-timed profiles of nyctohemeral changes that indicate a temporal (i.e., circadian) organization of cellular immune function, which is most likely of physiological significance in triggering and regulating immune responses. Such a molecular cytotoxic timetable can potentially serve as a guide to sampling during experimental, diagnostic, therapeutic and/or other medical procedures.
