Figure 2.
Two-dimentional mapping of the 47kDa RA autoantigen generated in ionomycin-activated neutrophils. Primary human neutrophils in HBSS containing 2 mM CaCl2 were incubated in the absence (A) or presence (B) of 1 µM ionomycin for 4 hrs at 37°C. Samples were resolved in the first dimension using 3–10 IPG strips and then by electrophoresis on 8% SDS-polyacrylamide gels. Proteins were visualized by Ponceau S staining (upper panel) prior to immunoblotting with RA patient sera (middle panel). Data from one representative serum is shown. Once the antigen was mapped, the spot was sliced from a GelCode blue-stained gel (lower panel) and used for protein sequencing. Note that the 47kDa species detected by RA sera (marked with the black arrow) is absent in control cells.