Fig. 9. Monoclonal antibodies raised against the tethering complex react against the 170 kDa subunit and can immunodeplete tethering activity. (A) Western analysis of monoclonal antibody staining of the 170 kDa component of the tethering factor. PS, position of protein standards. (B) Granules were incubated with anion-exchange-purified tethering factor (TF) or with an equivalent amount of tethering factor (15 µg) after it adsorption to protein G beads to which various (numbered columns) monoclonal antibodies had been bound. The activity depleted by protein G beads alone (in the absence of antibodies) has been subtracted from the antibody samples. One sample, a negative control, received IM buffer containing no tethering factor (No TF). Tethering activity was measured in the semi-quantitative assay. Significant immunodepletion (P<0.05) relative to the TF control is indicated for numerous monoclonal antibodies (identified by number). Error bars indicate s.d. (n=3).