Figure 2

HPV16 E5 decreases HLA-I surface expression in calnexin-containing but not in calnexin-deficient cells. CEM-C7 (calnexin) and CEM-NKR (no calnexin) cells were stably transfected with pCI-HPV16-E5-HA or pCI empty vector. A) Calnexin is only expressed in CEM-C7 cells but not in CEM-NKR cells. B) E5-HA expression was analysed in each stable polyclone by immunoprecipitation and -blot using mouse monoclonal anti-HA Ab and 500 μg RIPA cell lysate. C) FACS analysis of CEM-NKR and CEM-C7 cells transfected with either the empty vector pCI or with pCI-E5-HA were stained with anti-HLA-A, B, C mAbs B9.12. E5 expression results in diminished HLA-I surface staining in cells expressing calnexin, but not in calnexin deficient cells. D) The upper part of the blot shown in A was incubated with anti-HC-10 antibodies (anti HLA-B, C). Incubation with anti-actin antibodies was performed as loading control. Columns represent average values (N = 5) and the error bars comprise the corresponding standard deviations. There were no differences between the total amounts of cellular HLA (N = 5; pKW = 0.87, Kruskal-Wallis test, and pA = 0.77, ANOVA). Molecular-mass markers (in kDa) are indicated in the left of the blots.