THERAPEUTIC EFFECTS OF PREFERENTIAL INDUCTION OF MITE-SPECIFIC T-HELPER-0 CLONES

The predominance of Th2 cytokine-secreting pattern in allergic asthma has been known as a cause and an accelerating factor, and Th1 suppress es these allergic phenomena, but the role of Th0 clones is obscure. Be cause Th1/Th2 differentiation has been determined by cytokine environm ent, we investigated how mite-specific helper T cells stimulated in di fferent cytokine environments actually influenced IgE and IgG4 synthes is, which are known to be regulatory immunoglobulins for allergic resp onse. Th0 clones, which were mainly established in the presence of IL- 12, provided a great deal of help for IgG4 and IgG1 synthesis, but did not provide help for IgE synthesis, whereas Th2 clones helped IgE syn thesis prominently, and IgG4 and IgG1 synthesis marginally. These char acteristics of Th0 clones were also true for Th0 clones obtained from patients who were successfully treated with desensitization therapy. F urthermore, the differences in helper activity between Th0 and Th2 clo nes were not ascribed solely to soluble factors. These data indicate t hat IgE and IgG4 synthesis is differentially regulated by antigen-spec ific T cells, and that conversion or selection from Th2 to Th0 by the addition of IL-12 may exhibit therapeutic effects.