FIG 9.

Identification of fibronectin as an α₄β₇ binding component of CHO cell proteins. The CHO cell proteins were labeled with ¹²⁵I. (A) Comparison of proteins detected by autoradiography to 25 μg of proteins stained with Coomassie blue. Five major bands present in the Coomassie-stained gel were also identified by autoradiography, as indicated. (B) Proteins displayed α₄β₇-dependent binding to RPMI88666 cells after radiolabeling. (C) RPMI8866 cells were used to capture and identify α₄β₇ components. ¹²⁵I-labeled protein was captured on cells in the presence or absence of MAb 2B4, and then the cell-bound material was dissociated and analyzed. Input protein was compared to cell-bound material by SDS-PAGE and autoradiography. Shown are the original autoradiograph and a contrast-enhanced image. The cells retained a major band of approximately 260 kDa and a minor band of 55 kDa.