Figure 3.  TAP-deficient T2 cells transfected with Qa1 [T2Q cells] express extremely high levels of surface Qa1
	Peptide	Stained with
	0	Med
	Db	Med
	Qdm	Med
	0	anti-Qa1
	Db	anti-Qa1
	Qdm	anti-Qa1
	0	anti-Db
	Db	anti-Db
	Qdm	anti-Db
TAP-deficient human T2 cells transfected with Qa1 were stained with the anti-Qa1 mAb 4C2 following
incubation overnight at 26o with medium, 100uM of a Db-binding peptide WHMHHNMDLL, or 100uM
of the Qa1-binding peptide Qdm
Conclusions
1.  Surprisingly, TAP-deficient human T2 cells, that express negligible levels of HLA cI molecules, when
transfected with Qa1 express very high levels of Qa1 at the surface [even higher than expressed on L cells
transfected with Qa1, see Figure 2]
2.  The level of expression of Qa1 is not increased by overnight incubation with the Qa1-binding peptide, Qdm
3.  These and other data suggest that Qa1 is expressed at the surface of T2 cells in a stable peptide-
empty state in association with human b2m