The dose of foreign antigen can influence whether a cell-mediated or humoral class ofirm'nune response is elicited, and this may be largely accounted for by the development of CD4 + T helper cells (Th) producing distinct sets of cytokines. The ability of antigen dose to direct the development of a Thl or Th2 phenotype from naive CD4 + T cells, however, has not been demonstrated. In this report,...