Abnormalities in Intracellular Processing and Expression of Interferon-g Receptor in Adherent Cells From Lepromatous Leprosy Patients

Peripheral blood mononuclear cells in lepromatous leprosy (LL) patients produce low levels of interferon-g (IFN-g) and interleukin-12 (IL-12), and these cells exhibit partial or complete deficiency in the IL-12 receptor. The behavior of the IFN-g receptor (IFN-gR) has not been described in cells from people with leprosy. We found higher levels of mRNA for IFN-gR1 and IFN-gR2 in adherent cells stimulated with IFN-g and Mycobacterium leprae membrane proteins from LL patients compared with healthy subjects. Flow cytometry showed no significant difference in IFN-gR1 expression between LL patients and healthy subjects. Immunoblotting detected only the mature glycosylated form of the 61-67 kDa IFN-gR2 protein in healthy subjects. In contrast, cells from LL patients showed three different expression patterns: (1) the immature deglycosylated form of the 34.8 kDa IFN-gR2 protein, (2) the mature glycosylated 61-67 kDa form, and (3) both forms. Our data indicate the existence of abnormalities in the intracellular processing and protein expression of the IFN-gR in response to specific stimuli such as IFN-g and M. leprae membrane proteins in adherent cells of LL patients.