title: Lymphocytes bearing Fc receptors for IgE. V. Effect of tunicamycin on the formation of IgE-potentiating factor and IgE-suppressive factor by con A-activated lymphocytes.
abstract: Attempts were made to induce the formation of soluble factors having affinity for IgE (IgE-binding factors) by activated T cells. Normal rat mesenteric lymph node (MLN) cells were cultured in 1 microgram/ml Con A for 48 hr or in 10 microgram/ml Con A for 72 hr, and Con A-activated lymphocytes were incubated with rat IgE. It was found that IgE induced an increase in the proportion of Fc epsilon R(+) cells in the Con A-activated cells and formation of IgE-binding factors. However, the nature of IgE-binding factors formed by the cells were different depending on the concentration of Con A for activation. Thus, IgE-binding factors formed by 10 microgram/ml Con A-activated cells had a high affinity for lentil lectin and enhanced the IgE-forming cell response of DNP-OA primed cells. In contrast, the majority of IgE-binding factors formed by 1 microgram/ml Con A-activated cells failed to bind to lentil lectin and suppressed the IgE response. Induction of Fc epsilon R by IgE on Con A-activated cells was prevented by tunicamycin, which inhibits protein glycosylation. This antibiotic did not prevent the IgE-induced formation of IgE-binding factors but changed the nature of the factors formed by 10 microgram/ml Con A-activated cells. The majority of IgE-binding factors formed in the presence of tunicamycin lacked affinity for lentil lectin and Con A, and suppressed, rather than enhanced, the IgE response. The nature and amount of IgE-binding factors formed by 1 microgram/ml Con A-activated cells was not affected by tunicamycin. The results suggest that glycosylation of IgE-binding factors during their biosynthesis is an important step in determining their biologic function.
mesh_terms: D000818:Animals; D001666:Binding Sites, Antibody; D003208:Concanavalin A / Q000494:pharmacology; D005944:Glucosamine / Q000031:analogs & derivatives*; D007108:Immune Tolerance; D007073:Immunoglobulin E / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D051381:Rats; D011917:Rats, Inbred Lew; D011961:Receptors, Fc / Q000276:immunology*; D014415:Tunicamycin / Q000494:pharmacology*
chemical_list: D011961:Receptors, Fc; D003208:Concanavalin A; D014415:Tunicamycin; D007073:Immunoglobulin E; D005944:Glucosamine