Incubation with PPD of spleen cells of rats primed with BCG resulted in the formation of soluble factors having affinity for IgE, i.e., IgE-binding factors. The IgE-binding factors consisted of two different molecules; one had a m.w. of 60,000 to 80,000 and another molecule had a m.w. of between 10,000 and 20,000. The IgE-binding factors of both high and low m.w. selectively suppressed the IgE response to DNP-OA-primed cells to homologous antigen. Analysis of the cellular mechanisms of formation of IgE-suppressive factors revealed that the presentation of PPD to BCG-primed T cells by macrophages resulted in the formation of soluble factors that in turn induced normal MLN cells to form IgE-suppressive factors. Fractionation of the soluble factors from BCG-primed T cells on Poly U-Sepharose showed that two different factors, i.e., 'inducers' of IgE-binding factor and glycosylation-inhibiting factors, were involved in the selective formation of IgE-suppressive factors. The eluate fraction from Poly U-Sepharose induced normal MLN cells to form IgE-binding factors that had marginal suppressive activity on the IgE response. The effluent fraction from the beads failed to induce IgE-binding factors, but contained soluble factors that inhibited the glycosylation of IgE-binding factors during their biosynthesis and provided them with a biologic activity: suppression of the IgE response. The latter fraction also inhibited the IgE-induced expression of FcεR on the cell surface. In the BCG-primed spleen cells, the major source of both 'inducers' and glycosylation-inhibiting factors were W 3/25 (-) T cells, whereas the IgE-suppressive factors were derived from W 3/25 (+) T cells. The results collectively indicate that antigen-primed W 3/25 (-) T cells release both 'inducers' and glycosylation-inhibiting factors upon stimulation with PPD, and that these factors in combination stimulate W 3/25 (+) T cells to form IgE-suppressive factors.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1982|
ASJC Scopus subject areas
- Immunology and Allergy