Biochemical characterization and biological effects of partially purified B cell-activating factor (BCAF)

Eur J Immunol. 1988 Apr;18(4):577-84. doi: 10.1002/eji.1830180414.


B cell-activating factor (BCAF) has been characterized and partially purified from the supernatant of the murine tumor T cell line 373. BCAF has an apparent molecular mass of 15 to 20 kDa when analyzed by Superose 12 fast protein liquid chromatography (FPLC) gel filtration and a pI of 4.5 to 5.0 when analyzed by FPLC chromatofocusing. Concentrated supernatant was applied to a nickel chelating column and unadsorbed active material was further purified by two sequential C4 reverse-phase high-performance liquid chromatography steps. This purification procedure allowed a complete separation of interleukin 2 and interleukin 4 activities from BCAF. This partially purified BCAF induces Ia expression, cell size increase and proliferation of small resting B cells. Furthermore, we have shown that the activity of partially purified BCAF is insensitive to treatment by monoclonal antibodies specific for interleukin 4 and interleukin 5.

MeSH terms

  • Animals
  • B-Lymphocytes / cytology
  • B-Lymphocytes / physiology*
  • Histocompatibility Antigens Class II / biosynthesis
  • Interleukin-2 / biosynthesis
  • Interleukin-4
  • Interleukin-5
  • Interleukins / biosynthesis
  • Interleukins / isolation & purification*
  • Isoelectric Point
  • Lymphocyte Activation*
  • Mice
  • Molecular Weight
  • Tetradecanoylphorbol Acetate / pharmacology


  • Histocompatibility Antigens Class II
  • Interleukin-2
  • Interleukin-5
  • Interleukins
  • Interleukin-4
  • Tetradecanoylphorbol Acetate