The distribution of IL-13 receptor alpha 1 expression on B cells, T cells and monocytes and its regulation by IL-13 and IL-4

To study the expression of IL-13 receptor al (IL-13R alpha 1), specific mon oclonal antibodies (mAb) were generated. Surface expression of the IL-13R a lpha 1 on B cells, monocytes and T cells was assessed by flow cytometry usi ng these specific mAb. Among tonsillar B cells, the expression was the high est on the IgD(+) CD38(-) B cell subpopulation which is believed to represe nt naive B cells. Expression was also detectable on a large fraction of the IgD(-)CD38(-) B cells but not on CD38(+) B cells. Activation under conditi ons which promote B cell Ig class switching up-regulated the expression of the receptor. However, the same stimuli had an opposite effect for IL-13R a lpha 1 expression levels on monocytes. While IL-13R alpha 1 mRNA was clearl y detectable in T cell preparations, no surface expression was detected. Ho wever, permeabilization of the T cells showed a clear intracellular express ion of the receptor. A soluble form of the receptor was immunoprecipitated from the supernatant of activated peripheral T cells, suggesting that T cel l IL-13R alpha 1 might have functions unrelated to the capacity to form a t ype II IL-4/IL-13R with IL-4R alpha.