PEPTIDES BOUND ENDOGENOUSLY BY HLA-CW-ASTERISK-0304 EXPRESSED IN LCL-721.221 CELLS INCLUDE A PEPTIDE DERIVED FROM HLA-E

The peptide-binding specificity of HLA-Cw0304 was determined. Sequenc e analysis of endogenously-bound peptides isolated from Cw0304 expres sed by LCL 721.221 (221 for short) cells transfected with Cw0304 cDNA revealed this class I allotype preferentially binds peptides possessi ng alanine at position 2 and leucine or methionine at the C-terminus. One peptide isolated from Cw0304 expressed by 221 cells has sequence identity to residues 116-126 of HLA-E. Expression of HLA-E by 221 cell s was confirmed by isolation of mRNA transcripts for HLA-E0101 and de tection of beta 2-microglobulin (beta 2-m)-associated HLA-E protein.