INCREASED CLASS IB ANTIGEN DISPLAY ON TAP-2 MUTANT-CELLS BY A MITOCHONDRIAL-FUNCTION INHIBITOR

Class I histocompatibility antigen display is defective in the RMA-S m utant cell line due to a mutation in the Tap-2 gene, which encodes a p eptide transporter. Incubation of RMA-S cells with oligomycin, an inhi bitor of mitochondrial ATPase, strongly increased lysis by cytotoxic T lymphocytes (CTL) specific for the class Ib antigen H2-M3, and lysis by Qa-1(b)-specific CTL was restored. Oligomycin did not affect normal class I display on RMA cells. Treatment of RMA-S cells with other inh ibitors of mitochondrial function failed to increase lysis by anti-H2- M3 or Qa-1(b) CTL. Lysis by allogenic CTL specific for H-2(b) antigens was either not enhanced or only weakly increased, depending upon the H-2 haplotype of the alloreactive effector cells used. (C) 1997 Academ ic Press.