Clinical Features and Cytokine Profile in Myositis Patients with Anti-EJ Autoantibodies Detected by a Novel Immunoprecipitation Assay

Figure 2

Detection of anti-EJ antibodies in IIM patients using unlabeled protein immunoprecipitation assay. (a) IP using HEK293 lysate overexpressing GlyRS with flag tag. Sera from 236 IIM patients and 20 normal controls were assayed by IP. All 4 anti-EJ antibody-positive sera (YWN, M127, IM60, IM62) are shown, as well as some representative anti-EJ negative IIM sera. (b) Immunoblotting of HEK293 cells extracts without (lanes 1 and 2) or with pENTER-flag-GlyRS plasmids transfection (lanes 3 and 4) using IM60 sera as primary antibody. Both exogenous and endogenous GlyRS in HEK293 cells were specifically identified by IM60 sera. (c) IP assay of K-562 cell lysates using patient sera and immunoblot of precipitated proteins using anti-GlyRS antibody.

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