INTERFERON-GAMMA RECEPTOR BETA-CHAIN EXPRESSION AND FORMATION OF ALPHA-CHAIN AND BETA-CHAIN COMPLEXES AFTER RECEPTOR CONJUGATION ON HUMAN PERIPHERAL EOSINOPHILS

Background: It has been unclear whether or not the interferon-gamma re ceptor (IFN-gamma R) on human peripheral eosinophils is completely fun ctional. Accordingly, we examined the expression of IFN-gamma R alpha- and beta-chains and the association of the two chains after binding o f IFN-gamma R to the receptor. Methods: Peripheral blood eosinophils w ere obtained from 8 patients (bronchial asthma, n = 6, and hypereosino philic syndrome, n = 2), and expression of the alpha- and beta-chain w as investigated by flow cytometry with specific antibodies. Expression of mRNA for the alpha- and beta-subunits was also investigated by the reverse transcriptase-polymerase chain reaction. Results: Eosinophils from all the patients were positive for both the alpha- and beta-chai ns by flow cytometry. In addition, mRNA for both chains was detected b y the polymerase chain reaction. Furthermore, coprecipitation of the a lpha- and beta-chains was only found after eosinophil stimulation with IFN-gamma. Conclusions: Human peripheral eosinophils apparently expre ss both the alpha- and beta-chains of the IFN-gamma R, and the two cha ins may only form the receptor complex after ligand binding.