Stoichiometry of HLA Class II-Invariant Chain Oligomers
Figure 2
SDS-PAGE separation of Raji cell extracts from sucrose gradient fractions.
The lower panels depict densitometric scans of the western blots. A) Samples treated with SDS sample buffer at room temperature were SDS-PAGE separated and immunoblotted for DRα (monoclonal antibody TAL-1B5). The upper panel shows SDS resistant pDRαβ bands (ca. 55 kDa) in fractions 6 to 11. The Scan represents both the pDRαβ and the DRα bands. B) Immunoprecipitation (IP) of DRαβ with monoclonal antibody 16.23, and western blotting for DRα (upper panel). The monoclonal antibody 16.23 selectively immunoisolates DR from fraction 6 to 10 and shows no reactivity to DR in fractions 11 to 17. C) Immunoprecipitation from sucrose gradient fractions 6 to 17 with DR monoclonal antibody ISCR3. SDS-PAGE separation and western blotting for DRα (monoclonal antibody TAL-1B5) results in separation of two DR populations, which is visualized as two separate curves in the density scan.