The Role of IL-7 and Its Receptor in B-Cell Ontogeny
Interleukin-7 is a molecule that was originally identified on the basis of its ability to stimulate growth of murine pre-B cells (1). It appears to be principally a growth factor, not a differentiation factor, and has no effects on mature B cells. How early IL-7 acts in the pathway of B-lymphopoiesis has not been clearly defined; however, it is clear that other factors or signals are required at the very earliest stages of B-lymphopoiesis due to the necessity for contact with a stromal layer. In order to better understand the role of IL-7 in the context of the other factors which may influence B-lymphopoiesis, we have studied the effect of altering in vivo levels of IL-7 in mice. This has been done in three ways: first, by relatively short term administration of IL-7; second, through the generation of IL-7 transgenic mice which result in constitutive overexpression of IL-7; and third, through administration to mice of an anti-IL-7 antibody to remove the in vivo effects of IL-7. Although IL-7 has known effects on a number of cell lineages, the data presented here will concentrate primarily on what happens to the B-cell compartment.
KeywordsStromal Layer Enlarge Mesenteric Lymph Node Stromal Cell Layer Heat Stable Antigen Agar Bone Marrow
Unable to display preview. Download preview PDF.
- 1.A.E. Namen, A.E. Schmierer, C.J. March, R.W. Overell, L.S. Park, D.L. Urdal, and D.Y. Mochizuki, B cell precursor growth-promoting activity: purification and characterization of a growth factor active on lymphocyte precursors, J. Exp. Med. 167:988 (1988).Google Scholar
- 2.C.A. Whitlock, D. Robertson, and O.N. Witte, Murine B cell lymphopoiesis in long term culture, J. Immunol. Meth. 67:353 (1984).Google Scholar
- 3.R.R. Hardy, C.E. Carmack, S.A. Shinton, J.D. Kemp, and K. Hayakawa, Resolution and characterization of Pro-B and Pre-Pro-B cell stages in normal mouse bone marrow, J. Exp. Med. 173:1213 (1991).Google Scholar