Introduction

Figure 1.   Normal blast cells express very little Qa1 as judged by staining with the Qa1-specific mAb 4C2

Figure 2.   The low levels of Qa1 expressed on blast cells are sufficient to protect them from lysis by Qa1R⁺ NK cells

Figure 3.   TAP-deficient T2 cells transfected with Qa1 [T2Q cells] express extremely high levels of surface Qa1

Figure 4.   Despite their very high levels of surface Qa1 molecules, T2Q cells are not protected from lysis by Qa1R⁺ NK cells

Figure 5.   Qa1 molecules expressed on T2Q cells are functional as shown by their recognition by Qa1-specific CTL

Figure 6.   TAP-deficient T2Q cells, but not TAP-deficient RMA/S cells, can be protected from lysis by Qa1R⁺ NK cells following pre-incubation with Qdm peptide

Figure 7.   TAP-deficient RMA/S cells express levels of Qa1 that are barely detectable with the 4C2 mAb, even after incubation with Qdm peptide

Figure 8.   T2Q cells can be protected by Qdm peptide either by preloading or by the inclusion of peptide in the cytotoxicity assay

Figure 9.   Protection of T2Q cells by inclusion of peptide in the cytotoxicity assay occurs at peptide concentrations similar to or lower than those required for protection following overnight preloading

Figure 10.   Protection of T2Q cells by exogenous Qdm peptide occurs rapidly

Figure 11.   The protected state induced by incubation of T2Q cells with Qdm peptide is highly stable

Figure 12.   Approximately 20 fold higher concentrations of Qdm peptide [and presumably of surface Qa1-Qdm complexes] are required to protect cells from lysis by Qa1R⁺ NK cells than to sensitize them to lysis by Qa1-specific CTL

Figure 13.   100-1000 fold higher concentrations of peptide are required to sensitize RMA/S cells, compared to T2Q cells, to lysis by CTL

Figure 14.   The ability of natural and artificial Qdm-analogue peptides to protect T2Q cells from lysis by Qa1R +ve NK cells.

Acknowledgements.