Evidence for interactions between HLA system class I and beta-adrenergic receptors in human mononuclear leukocytes.
In order to determine the possible interactions between histocompatibility leukocyte antigen (HLA) -class I antigens and beta-adrenergic receptors, we evaluated the effects of anti-HLA class I monoclonal antibodies on beta-adrenoceptor-mediated intracellular production of cAMP in human mononuclear leukocytes. Moreover, we studied whether anti-HLA class I monoclonal antibodies inhibit the binding of a specific radioligand to the beta-adrenoceptors, and, conversely, whether both isoproterenol and propranolol interfere with the binding (evaluated by a cytofluorometric assay) of the anti-HLA class I monoclonal antibodies to the cell membrane. Our results showed that anti-HLA class I monoclonal antibodies induced a significant beta-adrenergic-dependent increase in intracellular cAMP whereas anti-HLA class II and antimelanoma monoclonal antibodies were ineffective. Moreover anti-HLA class I monoclonal antibodies inhibited, in part, the specific binding of a beta-adrenergic radioligand, although they did not induce the internalization of the beta-adrenoceptors. On the other hand, both isoproterenol and propranolol induced a significant decrease in the peripheral blood mononuclear cell expression of HLA-class I molecules. Our data suggest that important interactions between major histocompatibility complex gene products and the beta-adrenergic receptors may occur in human cells.
Pende
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Dipartimento Medicina Interne, Università di Genova, Italy.
Ioverno
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Setti
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Bosco
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Musso
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Vergassola
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Lanza
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Indiveri
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F
Lotti
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G
D000328:Adult; D000911:Antibodies, Monoclonal / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis; D000949:Histocompatibility Antigens Class II / Q000502:physiology*; D006801:Humans; D015151:Immunoblotting; D007545:Isoproterenol / Q000494:pharmacology; D009000:Monocytes / Q000502:physiology*; D010869:Pindolol / Q000378:metabolism; D011233:Precipitin Tests; D011433:Propranolol / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000502:physiology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D010869:Pindolol; D000242:Cyclic AMP; D007545:Isoproterenol