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Updated: Jul 30, 2026
Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
Intraglandular colloid induced nuclear proliferation of murine thymic cells as determined by flow cytometry
1College of Biological Sciences, School of Human Biology, University of Guelph, Ontario, Canada.
Insights
Bovine pituitary intermediate lobe colloid significantly boosts immature thymic cell proliferation in mice. This suggests neuropeptides in the colloid influence the immune system and pituitary lobe functions.
Area of Science:
- Endocrinology
- Immunology
- Cell Biology
Background:
- The bovine pituitary intermediate lobe secretes intraglandular colloid.
- The role of this colloid in immune system regulation is largely unknown.
- Immune cell proliferation is crucial for adaptive immunity.
Purpose of the Study:
- To investigate the effect of bovine intraglandular colloid on immature thymic cell proliferation.
- To determine if colloid neuropeptides modulate immune cell cycle dynamics.
Main Methods:
- CH3/6JH mice (4-6 weeks old) received subcutaneous injections of colloid or saline.
- Thymic cells were analyzed using propidium iodide staining and flow cytometry.
- Cell cycle phase distribution, specifically the S phase, was quantified.
Main Results:
- Colloid-injected mice showed a significant increase in thymic cells in the S phase (33%) compared to controls.
- Saline-injected controls had 15% of cells in S phase, while non-injected controls had 7%.
- This indicates enhanced proliferation of immature thymic cells upon colloid administration.
Conclusions:
- Intraglandular colloid from the bovine pituitary intermediate lobe promotes thymic cell proliferation.
- Neuropeptides within the colloid appear to play a role in immune system modulation.
- These findings reveal novel functions for the pituitary intermediate lobe beyond traditional endocrine roles.
Abstract:
The ability of intraglandular colloid, the holocrine secretion of cells of the marginal half of the bovine pituitary intermediate lobe, to enhance or suppress the proliferation of immature thymic cells of CH3/6JH mice, 4 to 6 weeks of age, was studied. The mice were given subcutaneous injections of colloid for 3 consecutive days at a dose of 20 mg/kg body weight in 0.2 ml of saline. The analysis of propidium iodide stained thymic cell preparations by means of flow cytometry showed that there was a significant increase in the percentage of cells in the S phase (proliferative phase) of the cell cycle of mice injected with colloid (33%) compared with saline injected (15%) and non-injected controls (7%). These findings are the first to suggest that various combinations and concentrations of intraglandular colloid neuropeptides play a role in the immune system and shed light on additional functions of the intermediate lobe.
