Activation or destruction of T cells via macrophages

Macrophages (M phi) affect the T cell response in two mutually exclusive wa ys: activation or deletion. A M phi, type with T cell activating functions (M1) is able to express and upregulate receptors of the B7 family, IFN-gamm a favours this M Phi, differentiation pathway via upregulation of CD80 (B7- 1) and CD86 (B7-2), The treatment of M Phi with IFN-gamma enhances the alph a CD3-mediated T cell blast transformation and reduces the fraction of dele ted T cells. This M Phi type may prevent antibody-mediated T cell destructi on by the expression of costimulatory receptors, An IL-10-induced M Phi typ e (M2) fails to express costimulatory molecules of the B7 family but is an effective cell for T cell destruction. Forming cellular conjugates with T c ells through antibodies or immune complexes, M2-M Phi preferentially delete targeted cells in vitro and in vivo. Copyright (C) 2000 S. Karger AG, Base l.