Figure 5. The observed effect of DO on peptide presentation is DO specific and can manifest in complex with DM.
(A) Association of HA(Y308A) peptide to DR1 molecules in the presence of coinfected DM/DO complex (Ni-NTA purified). The peptide binding experiment was performed with no accessory molecules (black squares), with DM (red dots), DM/DO (green triangles), or both DM/DO and DM (blue triangles) over the course of 10 hours. The fluorescence signals (Arbitrary Fluorescence Units) associated with the control samples incubated >10 hours in the absence of DR1 were measured: HA(Y308A) peptide alone, 1140; HA(Y308A)+DM, 894; HA(Y308A)+DM/DO, 1404; HA(Y308A)+DM+DM/DO, 1944. (B) DO was depleted from a DO stock by immunoprecipitation via Ni-NTA followed by Mags.DO5 resin. The depleted sample was used instead of DO in reactions measuring HA(anchorless) peptide/DR complex formation in the presence or absence of DM after 5 hours of incubation. The fluorescence intensity of peptide/DR1 complexes formed in the DO depleted reaction was compared to a reaction containing no DO (left bar in each set of three), and a reaction that contained DO that did not undergo depletion (right bar in each set of three). The experiment is representative of three separate trials. (C) A DO-depleted sample was used instead of DO in a reaction measuring of HA(306–318) peptide/DR complex formation in the presence or absence of DM after 5 hours of incubation. The fluorescence intensity of peptide/DR1 complexes formed in the DO depleted reaction was compared to a reaction containing no DO (left bar in each set of three), and a reaction that contained DO that did not undergo depletion (right bar in each set of three). The experiment is representative of three separate trials.