Interferon-Gamma Receptor Beta-Chain Expression And Formation Of Alpha- And Beta-Chain Complexes After Receptor Conjugation On Human Peripheral Eosinophils

Background: It has been unclear whether or not the interferon-gamma receptor (IFN-gamma R) on human peripheral eosinophils is completely functional. Accordingly, we examined the expression of IFN-gamma R alpha- and beta-chains and the association of the two chains after binding of IFN-gamma R to the receptor. Methods: Peripheral blood eosinophils were obtained from 8 patients (bronchial asthma, n = 6, and hypereosinophilic syndrome, n = 2), and expression of the alpha- and beta-chain was 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-chains by flow cytometry. In addition, mRNA for both chains was detected by the polymerase chain reaction. Furthermore, coprecipitation of the alpha- and beta-chains was only found after eosinophil stimulation with IFN-gamma. Conclusions: Human peripheral eosinophils apparently express both the alpha- and beta-chains of the IFN-gamma R, and the two chains may only form the receptor complex after ligand binding.