A transcription elongation factor complex that suppresses RNA polymerase II pausing, and may act by promoting proper alignment of the 3'-end of nascent transcripts with the polymerase catalytic site. Consists of a transcriptionally active Elongin A subunit (abut 100 kDa)and two smaller Elongin B (about 18 kDa) and Elongin C (about 15 kDa)subunits.