Cell-associated IL-8 in human blood monocytes: Analysis by flow cytometry

Seitaro Fujishima, Hidetoshi Nakamura, Yasuhiro Waki, Kenzo Soejima, Yuji Takeuchi, Motoyuki Ogawa, Masahide Shiozawa, Yoshiki Hiraoka, Takeo Kawashiro, Sadakazu Aiso, Minoru Kanazawa

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Several cell-associated cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor, exist on the cell surface and are biologically active. Although extracellular IL-8, a potent chemotactic factor for primarily neutrophils, has been studied extensively, cell-associated IL-8 has barely been studied. In this study, we analyzed the intracellular and cell-surface IL-8 in human blood monocytes in vitro by using flow cytometry and predicted the biological activity of the cell-associated IL-8 in vivo. After fixation with paraformaldehyde, mononuclear cells were divided into two subgroups. One subgroup was left untreated to study cell-associated antigens, and the other subgroup was permeabilized with saponin to detect intracellular antigens. In lipopolysaccharide (LPS)-stimulated monocytes, IL-8 was detected solely intracellularly, whereas both the intracellular and cell-surface IL-1β was detectable. In a time-course study, the intracellular IL-8 increased in response to LPS stimulation, but the cell-surface IL-8 was undetectable throughout he course. In an LPS-stimulated monocytic cell line, both ELISA and flow cytometry detected the quantitative change of the intracellular IL-8. The dissmilar localization between IL-8 and IL-1β within cells was confirmed by the immunohistochemical analysis. In summary, LPS stimulation induced a time-dependent increase in intracellular but not cell-surface IL-8 in monocytes. Thus, it is unlikely that the cell-associated IL-8 is functioning physiologically. The semiquantitative flow cytometric procedure may be useful for simultaneous examination for cell-surface and intracellular cytokines.

Original languageEnglish
Pages (from-to)382-389
Number of pages8
Issue number4
Publication statusPublished - 1996 Aug 1


  • Cell-associated cytokine
  • Flow cytometry
  • Immunohistochemistry
  • Interleukin-1β
  • Interleukin-8
  • Saponin

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Biophysics
  • Hematology
  • Endocrinology
  • Cell Biology


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