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Updated: Jul 26, 2026
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
Differences in pyrogen production by mononuclear phagocytes and by fibroblasts or HeLa cells
1Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
Abstract:
Phagocytosis of bacteria stimulates "professional" phagocytes to produce and release endogenous pyrogen (EP), the protein that mediates fever. To determine whether "nonprofessional" phagocytes also have this capacity, mouse and human fibroblasts and HeLa cells were cultured after ingestion of latex or chicken erythrocytes (CE), and EP release into culture supernate measured by mouse assay. No detectable pyrogen was released by these cell types after phagocytosis, whereas both latex and CE stimulated EP production by cultured mouse macrophages. These studies support the hypothesis that only professional phagocytes of bone marrow origin synthesize EP and induce fever.
Insights
Professional phagocytes, but not nonprofessional cells like fibroblasts, release endogenous pyrogen (EP) after phagocytosis. This suggests only professional phagocytes synthesize EP and induce fever.
Area of Science:
- Immunology
- Cell Biology
- Physiology
Background:
- Professional phagocytes produce endogenous pyrogen (EP), a fever-mediating protein, upon bacterial ingestion.
- The capacity of nonprofessional phagocytes to produce EP remains largely uncharacterized.
Purpose of the Study:
- To investigate whether nonprofessional phagocytes can produce and release endogenous pyrogen (EP) after phagocytosis.
- To determine if EP production is exclusive to professional phagocytes.
Main Methods:
- Mouse and human fibroblasts and HeLa cells were cultured and exposed to latex particles or chicken erythrocytes (CE).
- EP release into the culture supernatant was quantified using a mouse assay.
- Cultured mouse macrophages were used as a positive control for EP production.
Main Results:
- Nonprofessional phagocytes (fibroblasts, HeLa cells) did not release detectable levels of EP after phagocytosis.
- Both latex particles and CE stimulated significant EP production by cultured mouse macrophages.
- Phagocytosis by nonprofessional phagocytes did not lead to measurable EP release.
Conclusions:
- Only professional phagocytes, originating from bone marrow, possess the capacity to synthesize endogenous pyrogen (EP).
- Nonprofessional phagocytes do not contribute to EP synthesis or fever induction following phagocytosis.
- These findings support the hypothesis that EP production and fever are mediated exclusively by professional phagocytes.
