Expression of molecules involved in antigen presentation and T cell activation (HLA-DR, CD80, CD86, CD44 and CD54) by cultured human osteoblasts.
BACKGROUND
Osteoblasts express the CD44 antigen and HLA class II antigens, molecules which, together with other costimulatory molecules such as CD80, CD86, and CD54, are involved in antigen presentation and T cell activation. The aim of this study was to investigate the expression of these molecules in human osteoblasts.


METHODS
Human osteoblastic cells obtained from samples of normal bone obtained during mandibular osteotomy were isolated, maintained in culture, and characterized. The identity of the cells was confirmed by their alkaline phosphatase activity and their capacity to produce osteocalcin. Flow cytometry was used to examine the expression HLA-DR, CD80, CD86, CD44, and CD54 molecules involved in immune activities.


RESULTS
We detected the expression of CD10, CD44, and HLA-DR antigens, molecules involved in antigen presentation in cultured osteoblastic cells. Although the cells were negative for CD45, the leukocyte common antigen and CD14 (an antigen detected on macrophages), they expressed CD54, CD80, and CD86 antigens, which are also involved in the mechanisms of antigen presentation to and activation of T cells.


CONCLUSIONS
Our results suggest that osteoblastic cells or a subpopulation of these cells may have immune functions in bone. Further studies in which immune functions are assessed will be needed to test this hypothesis.
Reyes-Botella
C
C
Department of Stomatology, University of Granada, Spain.
Montes
M J
MJ
Vallecillo-Capilla
M F
MF
Olivares
E G
EG
Ruiz
C
C
D000328:Adult; D000469:Alkaline Phosphatase / Q000032:analysis; D017951:Antigen Presentation / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology*; D018122:B7-1 Antigen / Q000276:immunology; D051940:B7-2 Antigen; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000276:immunology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000276:immunology; D018950:Lipopolysaccharide Receptors / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D008334:Mandible / Q000166:cytology; D008562:Membrane Glycoproteins / Q000276:immunology; D015260:Neprilysin / Q000276:immunology; D010006:Osteoblasts / Q000276:immunology*; D015675:Osteocalcin / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D006684:HLA-DR Antigens; D018960:Hyaluronan Receptors; D018950:Lipopolysaccharide Receptors; D008562:Membrane Glycoproteins; D015675:Osteocalcin; D018799:Intercellular Adhesion Molecule-1; D000469:Alkaline Phosphatase; D017493:Leukocyte Common Antigens; D015260:Neprilysin