Immunoprecipitation of myositis-specific autoantibodies. Ten percent SDS-PAGE of immunoprecipitates of [35S] labeled K562 cell extract. Lane 1: normal serum; lane 2: anti-PL7; lane 3: anti-PL12; lane 4: anti-Zo; lane 5: anti-Jo-1; lane 6: anti-OJ; lane 7: anti-KS; lane 8: anti Ha (unconfirmed); lane 9: anti-Mi-2; lane 10: anti-SRP; lane 11: anti-p155/140 (TIF1-γ); lane 12: anti-SAE; and lane 13: anti-p140 (NXP2). Myositis-specific autoantibodies not shown include anti-EJ, anti p100/200, and anti-CADM-140 (MDA5). CADM, clinically amyopathic dermatomyositis; MDA5, melanoma differentiation-associated gene 5; NXP2, nuclear matrix protein 2; SAE, small ubiquitin-like modifier activating enzyme 1 and 2; SRP, signal recognition particle; TIF1-γ, transcription intermediary factor 1 gamma.