Fig. 1.

Distribution of predicted HLA class I ligands of viral origin. All predicted ligands of the 20 most frequent HLA-A and HLA-B molecules in US subpopulations of a certain ethnic background (European, African, Asian and Hispanic) were classified into three categories: unique ligands (exclusively presented by one HLA class I molecule), within-supertype promiscuous ligands (exclusively targeted by one HLA supertype, but presented by at least two class I HLA molecules within this supertype) and across-supertype promiscuous ligands (targeted by HLA molecules belonging to at least two different HLA supertypes)