|
||
J. Exp. Med.,
Volume 189, Number 9, May 3, 1999 1413-1423
By

From the * Ludwig Institute for Cancer Research, Experimental Medicine Unit, University of Louvain,
B-1200 Brussels, Belgium; and the The activity of interleukin (IL)-9 on B cells was analyzed in vivo using transgenic mice that
constitutively express this cytokine. These mice show an increase in both baseline and antigen-specific immunoglobulin concentrations for all isotypes tested. Analysis of B cell populations
showed a specific expansion of Mac-1+ B-1 cells in the peritoneal and pleuropericardial cavities, and in the blood of IL-9 transgenic mice. In normal mice, the IL-9 receptor was found to
be expressed by CD5+ as well as CD5
University of Cape Town, 7925 Cape Town, South Africa
B-1 cells, and repeated injections of IL-9 resulted in
accumulation of B-1 cells in the peritoneal cavity, as observed in transgenic animals. Unlike
other mouse models, such as IL-5 transgenic mice, in which expansion of the B-1 population is
associated with high levels of autoantibodies, IL-9 did not stimulate the production of autoantibodies in vivo, and most of the expanded cells were found to belong to the B-1b subset
(IgM+Mac-1+CD5
). In addition, we found that these IL-9-expanded B-1b cells do not share
the well-documented antibromelain-treated red blood cell specificity of CD5+ B-1a cells. The
increase of antigen-specific antibody concentration in immunized mice suggests that these B-1
cells are directly or indirectly involved in antibody responses in IL-9 transgenic mice.
This article has been cited by other articles:
| TABLE OF CONTENTS |
|