UTILIZATION OF THE MHC CLASS-I (H-2K(B)) PURIFIED MOLECULE AND ITS SYNTHETIC PEPTIDES FOR INHIBITION OF K(B)-SPECIFIC SUPPRESSOR T-CELLS AND THEIR INDUCTION INVIVO BY THE MHC PEPTIDES

Six synthetic peptides of the MHC class I molecule corresponding to in dividual H-2K(b) participants in amino acid sequences of domains alpha 1 (peptide 1 and 2) and alpha2 (peptides 3, 4, 5, 6) were selected. K( b)-specific suppressor T cells (Ts) were induced in vivo in mice, then pretreated with a set of peptides and assayed by proliferation decrea se in a three-cell lymphocyte culture (MLC). The effector function of Ts was abolished by the complex of the alpha2-domain peptides (but not by the alpha1-domain peptides) and decreased by particular peptides s eparately (4, 5, 6) of the alpha2-domain. Both alpha1- and alpha2-doma in peptides, added in high concentration, decreased otherwise efficien t enrichment of Ts during the absorption-elution procedure on the syng eneic macrophage (Mphi) monolayers. A similar significant effect was o bserved using the purified K(b) molecule (100 mug/ml) in the allogenei c Mphi monolayer. Interaction between Ts receptors and some MHC peptid es indicates in effector Ts activation in vivo by induction with pepti des 5 and 6 of the alpha2-domain. The fine mechanisms of interaction b etween MHC class I molecule epitopes and T-cell receptors of each of t he T-cell subsets separately are presently being studied.