Secretion patterns of Th1- and Th2-type cytokines in immune deviation caused by dendritic cells.

The expression of cytokine mRNAs in mice during immune deviation was examined. A subcutaneous injection of antigen-pulsed dendritic cells (DCs) induced strong delayed-type hypersensitivity (DTH) but not humoral immunity, but an intravenous injection of DCs increased the titer of specific antibodies while inducing weak DTH. There was more interleukin-4 and interleukin-5 mRNA in mice given DCs subcutaneously than in those given DCs intravenously. Therefore, synthesis of cytokines from type 2 helper T (Th2) cells was greater when there was DTH but little or no antibody production. This pattern of cytokine synthesis was in accordance with the pattern of isotypes of the specific antibodies produced. In the mice given DCs intravenously, there was more mRNA of Th1 cytokines, and the production of IgG2a, IgG2b, and IgG3 antibodies increased, but that of IgG1 antibody did not. In immune deviation induced by antigen-pulsed DCs, cross-regulation of Th1 and Th2 cells may be more complicated.