Rapid secretion of interleukin-1beta by microvesicle shedding

Immunity. 2001 Nov;15(5):825-35. doi: 10.1016/s1074-7613(01)00229-1.


The proinflammatory cytokine interleukin-1beta (IL-1beta) is a secreted protein that lacks a signal peptide and does not follow currently known pathways of secretion. Its efficient release from activated immune cells requires a secondary stimulus such as extracellular ATP acting on P2X(7) receptors. We show that human THP-1 monocytes shed microvesicles from their plasma membrane within 2-5 s of activation of P2X(7) receptors. Two minutes after such stimulation, the released microvesicles contained bioactive IL-1beta, which only later appeared in the vesicle-free supernatant. We conclude that microvesicle shedding is a major secretory pathway for rapid IL-1beta release from activated monocytes and may represent a more general mechanism for secretion of similar leaderless secretory proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Humans
  • Interleukin-1 / immunology*
  • Interleukin-1 / metabolism*
  • Microscopy, Electron, Scanning
  • Monocytes / immunology*
  • Monocytes / ultrastructure
  • Secretory Vesicles / immunology
  • Secretory Vesicles / ultrastructure


  • Interleukin-1