Characterization and variability of the CFHR1/CFHL1 region. (A) Two-dimensional electrophoretic analysis of the heparin-sepharose eluate obtained from control person C1, followed by Western blot with a polyclonal antibody preparation recognizing CFHR1 and CFHL1, or with a monoclonal antibody specific for CFHL1. Only the gel area corresponding to the CFHR1/CFHL1 region is shown. Spots numbered from 1 to 6 were picked up from a replicate gel stained with Coomassie and were identified as CFHR1 by matrix-assisted laser desorption-ionization time-of-flight spectrometry in a 4700 Proteomics Analyzer (PerSeptives Biosystems). (B) CFHR1 isoforms observed after 2DE and Western blot analysis of heparin-sepharose eluates from different control persons. C1 to C7 indicate individual samples; P, pooled-control sample. Isoforms characteristic of patterns A or B are labeled. Arrows indicate CFHL1 isoforms. A scheme of the 3 isoform patterns observed is shown on the right. The molecular weights (kDa) of the CFHR1 isoforms are indicated at the left.