Figure 5 Stability of interferonγ receptor 1 (IFNγR1) in HEK 293 cells transfected with the wild‐type (WT), 774del4 or 818del4 forms of IFNGR1. The WT, 774del4 and 818del4 IFNGR1 cDNAs were introduced into the HEK 293 using the calcium phosphate method. At 24 hours after transfection, the cells were treated with 20 μg/ml cycloheximide for 3 hours. The expression levels of IFNγR1 were analysed by flow cytometry and Western blotting using monoclonal mouse antibodies against human IFNγR1. (A) IFNγR1 analysed by flow cytometry. (a) WT; (b) 774del4; (c) 818del4; solid line, cycloheximide‐treated cells; dotted line, untreated cells. (B) The lysates of cells transfected with WT and 774del4 IFNγR1 were analysed by Western blotting. The cells were treated with CHX (a, c) or untreated (b, d).