Journal of Clinical Endocrinology & Metabolism, Vol 77, 1329-1333, Copyright © 1993 by Endocrine Society

ARTICLES

Evidence for interactions between HLA system class I and beta- adrenergic receptors in human mononuclear leukocytes

A Pende, A Ioverno, M Setti, O Bosco, NR Musso, C Vergassola, L Lanza, F Indiveri and G Lotti
Dipartimento Medicina Interne, Universita di Genova, Italy.

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.