A QUANTITATIVE ASSAY OF PEPTIDE-DEPENDENT CLASS-I ASSEMBLY

We have developed a quantitive assay for the measurement of class I assembly induced by peptide. We have applied this assay to H-2D(b), K(b) and HLA-A2.1 with a panel of 49 overlapping peptides derived from HIV-1 gag protein. We find that the effects of peptide on assembly form a continuous distribution. By defining positives as those that increase the concentration of folded heavy chains more than three standard deviations from the control we show that 7/48 bind A2.1, 11/49 bind D(b) and 7/47 bind K(b). The assembly assay contrasts with solid-phase assays in being more discriminating (fewer peptides binding any given class I molecule), and showing less overlap in the patterns of peptides bound by the three class I molecules.