Interleukin 2 and low molecular weight B cell growth factor are T cell-replacing factors for different subpopulations of human B cells.
Both recombinant human interleukin 2 (rhIL 2) and low molecular weight B cell growth factor (BCGFlow) were shown to be T cell-replacing factors (TRF) in specific antibody responses to influenza virus by human blood and tonsillar B cells. When B cells were separated into high and low-density populations on Percoll gradients at 1.074 kg/l, IL 2 was found to act as a TRF only on the low-density B cells, whereas BCGFlow was a TRF for high-density B cells with a lesser effect on low-density B cells. Both populations of B cells responded well in the presence of T cells. The high-density B cells could not be activated to respond to IL 2 by either IL 1, rhIL 4 or by a CD22 monoclonal antibody known to enhance B cell activation. In contrast, a 24-h preincubation with T cells and antigen appeared to prime high-density B cells to respond to IL 2. These results show that high-density B cells can in fact respond to TRF, and that IL 2 and BCGFlow act on different populations of B cells which may be defined by prior exposure to T cells.
Callard
R E
RE
Department of Immunology, Institute of Child Health, London, GB.
Smith
S H
SH
D001402:B-Lymphocytes / Q000145:classification / Q000502:physiology*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000502:physiology*; D015847:Interleukin-4; D015848:Interleukin-5; D007378:Interleukins / Q000502:physiology*; D008213:Lymphocyte Activation; D008970:Molecular Weight
D007376:Interleukin-2; D015848:Interleukin-5; D007378:Interleukins; D015847:Interleukin-4