In vitro spontaneous osteoclastogenesis of human peripheral blood mononuclear cells is not crucially dependent on T lymphocytes.

Abstract

OBJECTIVE:

In vitro spontaneous osteoclastogenesis from peripheral blood mononuclear cells (PBMCs) is increased in diseases with excessive bone loss. The purpose of this study was to reassess the role of T lymphocytes in this process.

METHODS:

Fresh or cryopreserved PBMCs obtained from healthy subjects and from patients with rheumatoid arthritis, psoriatic arthritis, and non-psoriatic spondylarthritis were cultured at high density and stained for tartrate-resistant acid phosphatase (TRAP). Resorption of mineralized matrix was assessed by a dentin disc assay. CD14+ monocytes and CD3+ T cells were selected using magnetically labeled antibodies.

RESULTS:

Numerous multinucleated, TRAP+, dentin-resorbing osteoclasts developed spontaneously from fresh PBMCs from healthy individuals. This process was abrogated by T cell depletion and was restored by exogenous macrophage colony-stimulating factor (M-CSF) and RANKL, indicating the important role of T cells in spontaneous osteoclastogenesis in vitro. Using physiologic freezing and thawing as a model for the activation of PBMCs, spontaneous osteoclastogenesis was significantly increased in cryopreserved versus fresh cells. Under these conditions, spontaneous osteoclastogenesis was not dependent on T lymphocytes, since it was not influenced by T cell depletion and persisted in purified CD14+ cell cultures supplemented with M-CSF and RANKL. In contrast to studies with fresh PBMCs, spontaneous osteoclastogenesis under these conditions did not appear to be clearly different between healthy subjects and patients with arthritis.

CONCLUSION:

Spontaneous osteoclastogenesis in vitro is dependent on T lymphocytes or on the direct activation of monocytic cells, depending on the test conditions. This variability warrants better validation of the relevance of this functional test for in vivo osteoclastogenesis.

• Authors: Bernard Vandooren, Lode Melis, Eric M Veys, Paul P Tak, Dominique Baeten
• Journal: Arthritis and rheumatism (Arthritis Rheum) Vol. 60 Issue 4 Pg. 1020-5 (Apr 2009) ISSN: 0004-3591 [Print] United States
• PMID: 19333923 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• CD3 Complex
• Lipopolysaccharide Receptors

Topics

• Adolescent
• Adult
• Aged
• Arthritis, Psoriatic (immunology, pathology)
• Arthritis, Rheumatoid (immunology, pathology)
• Bone Resorption (immunology, pathology)
• CD3 Complex (metabolism)
• Cell Communication (immunology)
• Cell Differentiation (immunology)
• Female
• Humans
• In Vitro Techniques
• Lipopolysaccharide Receptors (metabolism)
• Male
• Middle Aged
• Monocytes (cytology, immunology, metabolism)
• Osteoclasts (cytology, immunology)
• Rheumatic Diseases (immunology, pathology)
• Spondylarthritis (immunology, pathology)
• T-Lymphocytes (cytology, immunology, metabolism)
• Young Adult