Production of B cell growth factor by normal human B cells.
Although it has been demonstrated that malignant human B cell lines are capable of producing B cell growth factor (BCGF), production of BCGF by normal B cells has not been shown. In this study, we demonstrate BCGF production by normal B cells, achieved by using human peripheral blood B cells prepared by a positive selection technique and stimulated with Staphylococcus aureus Cowan I (SAC) for 12 hr. SAC was removed from the supernatants by anti-SAC-coupled Sepharose. Supernatants absorbed with this antibody were functionally free of SAC, as demonstrated by their inability to activate resting B cells. B cells stimulated with SAC for 12 hr produced BCGF activity that was generally unmeasurable in supernatants by 36 hr. Characterization of BCGF produced by SAC-stimulated B cells revealed a m.w. of 32,000 by high-performance liquid chromatography sieving and sodium dodecyl sulfate-polyacrylamide gel electrophoresis; this BCGF was found to have an isoelectric point of 6.7. Furthermore, this BCGF lacked interleukin 1, interleukin 2, interferon, and B cell differentiation factor activity. This observation that BCGF can be produced by normal human B cells is significant because it demonstrates for the first time that normal B cells have the ability to provide their own growth factors or the growth factors for other B cells.
D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002469:Cell Separation; D002474:Cell-Free System; D002851:Chromatography, High Pressure Liquid; D006133:Growth Substances / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D006801:Humans; D007163:Immunosorbent Techniques; D015847:Interleukin-4; D007525:Isoelectric Focusing; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D008970:Molecular Weight; D013205:Staphylococcal Protein A / Q000494:pharmacology
D006133:Growth Substances; D008222:Lymphokines; D013205:Staphylococcal Protein A; D015847:Interleukin-4