In vivo treatment with an appropriate anti-Thy-1.2 monoclonal antibody abrogates hybrid resistance to Thy-1.1+ virus-immune effector T cells.

The hybrid resistance (Hr) effect operates to limit the induction of T-cell-mediated inflammatory processes following transfer into recipients injected with murine lymphocytic choriomeningitis virus (LCMV). Adoptively transferred Thy-1.1+ H-2b (KbDb) LCM virus-immune T cells are inhibited in cyclophosphamide (Cy)-suppressed, virus-infected mice that are heterozygous for H-2Db (e.g. H-2k x b F1). Injection of recipient animals with monoclonal antibody (mAb) to Thy-1.2 resulted in the elimination of Thy-1.2+ H-2b x d F1 effectors on transfer to H-2b x d F1 recipients. The Hr effect was removed by mAb treatment of Thy-1.2+ F1 recipients given H-2b Thy-1.1+-immune T cells. Apparently Hr is mediated by a cell which is Thy-1+.