Polyinosinic acid: polycytidylic acid promotes T helper type 1‐specific immune responses by stimulating macrophage production of interferon‐α and interleukin‐12

Abstract

The effects exerted on the development in vitro of Dermatophagoides pteronyssinus group I (Der p I)‐specific T cell lines and T cell clones by addition of polyinosinic acid: polycytidylic acid (poly I:C) in lymphocyte bulk culture were examined. Der p I‐specific T cell lines generated in presence of poly I:C exhibited reduced ability to produce interleukin (IL)‐4 and IL‐5 and developed into Der p I‐specific CD4⁺ T cell clones showing a T helper (Th) type 0 or Th1, instead of Th0/Th2 cytokine profile. This effect was prevented by addition to lymphocyte bulk cultures of a mixture of antibodies specific for interferon (IFN)‐α and IL‐12, whereas the addition of anti‐IFN‐α or anti‐IL‐12 antibody alone was uneffective. Poly I:C also showed the ability to stimulate the production of noticeable amounts of both IFN‐α and IL‐12 by human monocytes. Taken together, these data suggest that poly I:C is a Th1‐inducing agent whose activity is mediated by its ability to stimulate the production of IFN‐α and IL‐12 by monocytes.