T cells are able to promote lipopolysaccharide-induced bone resorption in mice in the absence of B cells.
OBJECTIVE
T cells and their cytokines are believed to be key factors in periodontal disease and bone resorption. We previously showed that T cells transferred to nude mice were related to inflammatory bone resorption in vivo. However, it has not been clarified whether T cells can induce bone resorption in the absence of B cells. In this study, we therefore investigated the ability of T cells to induce bone resorption without B cells, using both T cell- and B cell-deficient mice with severe combined immune deficiency (SCID).


METHODS
Escherichia coli lipopolysaccharide (LPS) was injected into the gingivae of SCID mice reconstituted by T cells (SCID + T mice). Wild-type C.B-17 mice and SCID mice were used as control animals. Alveolar bone resorption and production of cytokines in the gingivae were then compared histopathologically and immunohistologically.


RESULTS
The degree of bone resorption in SCID + T mice was significantly greater than that in SCID mice but less than that in wild-type mice. The same tendency was found for expression of receptor activator of nuclear factor kappaB ligand. The number of interferon-gamma-positive cells in SCID + T mice was the highest of the three groups. In contrast, interleukin-4-positive cells were detected in wild-type mice but not in SCID + T and SCID mice.


CONCLUSIONS
The results suggest that T cells are able to promote LPS-induced bone resorption in the absence of B cells. The expressions of cytokines in the presence of B cells are quite different.
Yamaguchi
M
M
Department of Periodontology, Unit of Translational Medicine, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Ukai
T
T
Kaneko
T
T
Yoshinaga
M
M
Yokoyama
M
M
Ozaki
Y
Y
Hara
Y
Y
D016301:Alveolar Bone Loss / Q000276:immunology*; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism; D017252:CD3 Complex / Q000032:analysis / Q000096:biosynthesis; D005260:Female; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis / Q000096:biosynthesis; D015847:Interleukin-4 / Q000032:analysis / Q000096:biosynthesis; D008070:Lipopolysaccharides; D008297:Male; D051379:Mice; D016513:Mice, SCID; D053245:RANK Ligand / Q000032:analysis / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D017252:CD3 Complex; D008070:Lipopolysaccharides; D053245:RANK Ligand; D015847:Interleukin-4; D007371:Interferon-gamma