Mouse splenic macrophage cell lines with different antigen-presenting activities for CD4 + helper T cell subsets and allogeneic CD8 + T cells

Abstract

A panel of seven mouse splenic macrophage cell lines, derived from cloned progenitors, was compared for their ability to present antigen to Th 1 or Th 2 helper T cell lines and hybridomas, as well as to naive T cells, and to provide accessory cell function for the synthesis of antibody from primed B cells. One of the cell lines expressed MHC class II molecules and was the only line with constitutive antigen-presenting activity for Th 1 cells. It may represent a subset of splenic macrophages responsible for the activation of naive Th 1 helper cells in situ. The remaining six cell lines responded to INF-γ by up-regulating their class II expression and acquiring Th 1 antigenpresenting activity. They may represent cells which, in situ, lack constitutive antigen-presenting activity but are promoted to presenting status by Th 1-derived INF-γ. Five of the cell lines provided accessory cell function to Th 2 cells, as indicated by antibody synthesis in suspensions of spleen cells from primed mice depleted of their antigen-presenting cells. One of the cell lines lacking accessory cell activity had constitutive antigen-presenting activity for Th 1 cells. This reciprocal expression of antigen-presenting activity supports the idea that Th 1 and Th 2 helper cells are activated by different antigen-presenting cells. Finally, the cell lines differed in their ability to constitutively induce an allogeneic response; a response that was limited to CD8 + T cells occurred in a CD4 + helper cell-independent manner and was unaffected by the addition of INF-γ. The alloantigenpresenting macrophage cell lines also possessed the most efficient accessory cell activity for antibody synthesis. These cell lines, which represent a spectrum of antigen-presenting activities in the spleen afford models for defining the roles of macrophages in the induction of immune responses and for resolving issues concerning their development.