Functional expression of the calcitonin receptor by human T and B cells.
The calcitonin receptor (CTR) is a seven-transmembrane-domain G-protein-coupled receptor that regulates calcium metabolism and bone resorption by osteoclasts. Here we demonstrate that high levels are expressed by normal human T and B lymphocytes from tonsils and peripheral blood in relation to their activation status, as CTR(+) T cells are prone to produce IFN-gamma after TCR stimulation. The receptor is also highly expressed on B cells from chronic lymphocytic leukemia patients, thus suggesting a correlation between its expression, their proliferative extent as well as their memory, antigen-experienced phenotype. Moreover, we found that binding of the receptor with salmon calcitonin induces an increase of intracellular calcium(2+) in peripheral lymphocytes. This effect is involved in several lymphocyte immune functions, as cytosolic calcium(2+) levels regulate both cell proliferation and cytokine production. In our hands, the increase of calcium(2+) levels by CTR binding with sCT induced a dose-dependent cell proliferation. We therefore suppose that expression of this functional receptor may contribute to the modulation of cytoplasmic calcium(2+) levels needed to regulate T and B cell activation and perhaps other immune functions.
Cafforio
Paola
P
Department of Internal Medicine and Clinical Oncology, University of Bari, Bari, Italy.
De Matteo
Monica
M
Brunetti
Anna Elisabetta
AE
Dammacco
Franco
F
Silvestris
Franco
F
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014066:Palatine Tonsil / Q000473:pathology; D018003:Receptors, Calcitonin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D012474:Salmon; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
D018003:Receptors, Calcitonin; D002118:Calcium