Human recombinant IL-3 is a growth factor for normal B cells

J Immunol. 1992 Jan 15;148(2):491-7.

Abstract

IL-3 is a well known hemopoietic cell growth and differentiation factor. However, its functional role in normal B cell differentiation has not been established. We have investigated the effect of IL-3 on the growth and differentiation of human B cells. IL-3 enhanced the proliferation of Staphylococcus aureus Cowan 1 strain-stimulated B cells. The optimal time of IL-3 to stimulate B cell growth was on day 2 to day 3, suggesting that IL-3 was a B cell growth factor acting in the late stage. IL-3 synergized with IL-2 to enhance B cell proliferation and differentiation. Pretreatment of B cells with IL-3 for more than 3 days increased the expression of IL-2R on B cells. However, pretreatment of B cells with IL-2 did not alter the subsequent response to IL-3, suggesting that the synergy between IL-2 and IL-3 may be attributed to the up-regulation of IL-2 response by IL-3. In addition, pretreatment of B cells with IL-4 decreased subsequent response of B cells to IL-3 as well as IL-2, suggesting that IL-3- and IL-2-responding cells passed a similar way during the early stage of B cell activation. It appears that IL-3 and IL-6 mediate normal B cell differentiation via separate mechanisms. IL-3-induced B cell differentiation was mainly mediated by increasing cell growth, whereas IL-6 induced B cell differentiation without affecting proliferation.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • B-Lymphocytes / drug effects*
  • Cell Differentiation / drug effects
  • Drug Synergism
  • Growth Substances / pharmacology*
  • Humans
  • Interleukin-2 / pharmacology
  • Interleukin-3 / pharmacology*
  • Interleukin-4 / pharmacology*
  • Interleukin-6 / pharmacology
  • Lymphocyte Activation / drug effects
  • Receptors, Interleukin-2 / analysis
  • Recombinant Proteins / pharmacology

Substances

  • Growth Substances
  • Interleukin-2
  • Interleukin-3
  • Interleukin-6
  • Receptors, Interleukin-2
  • Recombinant Proteins
  • Interleukin-4