title: Modulation of the biologic activities of IgE-binding factors. III. Switching of a T cell hybrid clone from the formation of IgE-suppressive factor to the formation of IgE-potentiating factor.
abstract: Incubation of rat-mouse T cell hybridoma cells, 23B6, with rat immunoglobulin E (IgE) results in the formation of the 15,000-dalton IgE-suppressive factor and the 30,000-dalton IgE-binding factor, which has neither potentiating activity nor suppressive activity on the IgE response. Another T cell hybridoma, 23A4 cells, produces the 30,000-dalton "inactive" IgE-binding factor upon incubation with IgE. Both the 15,000-dalton IgE-suppressive factor and the 30,000-dalton IgE-binding factor lacked affinity for lentil lectin but bound to peanut agglutinin. When the 23B6 cells were incubated with IgE in the presence of lysolecithin, the majority of the 15,000-dalton IgE-binding factor formed by the cells gained affinity for lentil lectin, and this factor selectively potentiated the IgE response. The glycosylation-enhancing factor, which was formed by stimulation of normal spleen cells with lymphocytosis-promoting factor (LPF or pertussigen), also switched 23B6 cells from the formation of IgE-suppressive factor to the formation of IgE-potentiating factor. It was also found that the 30,000-dalton "inactive" IgE-binding factor, formed by both 23B6 and 23A4 cells, gained the ability to potentiate the IgE response, when the cells were cultured with IgE in the presence of glycosylation-enhancing factor. The results indicate that IgE-potentiating factor and IgE-suppressive factor share common precursors, and that biologic activities of IgE-binding factors are decided by their carbohydrate moieties. Incubation of the two hybridoma cells with lysolecithin or glycosylation-enhancing factor results in an increase in the proportion of FC epsilon R+ cells, suggesting that the assembly of N-linked oligosaccharide to precursor molecules is intrinsic for the expression of FC epsilon R.
mesh_terms: D000818:Animals; D017302:Annexins; D001798:Blood Proteins / Q000096:biosynthesis* / Q000502:physiology; D002135:Calcium-Binding Proteins; D002999:Clone Cells / Q000276:immunology; D006023:Glycoproteins; D008222:Lymphokines / Q000096:biosynthesis* / Q000502:physiology; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D051379:Mice; D008970:Molecular Weight; D029584:Prostatic Secretory Proteins; D011506:Proteins / Q000276:immunology; D051381:Rats; D011917:Rats, Inbred Lew; D011961:Receptors, Fc / Q000378:metabolism; D017455:Receptors, IgE; D017452:Receptors, IgG; D011971:Receptors, Immunologic / Q000378:metabolism*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D017302:Annexins; D001798:Blood Proteins; D002135:Calcium-Binding Proteins; D006023:Glycoproteins; D008222:Lymphokines; D008244:Lysophosphatidylcholines; D029584:Prostatic Secretory Proteins; D011506:Proteins; D011961:Receptors, Fc; D017455:Receptors, IgE; D017452:Receptors, IgG; D011971:Receptors, Immunologic; C043076:beta-microseminoprotein; C011850:immunoenhancing factor; C013059:immunoglobulin-binding factors; C030958:lipomodulin