Figure 7.

Effect of antibodies to LTBP-1 on matrix incorporation of LTBP-1. (A) Subconfluent cultures of HT 1080 and BAE cells were treated during the 3-h pulse and overnight chase labeling period with either protein A–purified nonimmune IgG or affinity-purified IgGs (20 μg/ml) generated against GST-450, GST1065, or GST-849. HT 1080 cultures also received 50 μg/ml aprotinin to prevent degradation of exogenously added antibodies. Matrix digests were prepared and immunoprecipitated using Ab 39 followed by SDS-PAGE and fluorography. (B) Matrix incorporation reactions of ³⁵S-labeled BAE CM and UMR-106 ECMs were done in the absence (−) of additions or in the presence of protein A–purified non-immune rabbit IgG or affinity-purified IgGs (20 μg/ml) generated against GST-450, GST-1065, and GST-849. Matrix digests were prepared as previously described and their LTBP-1 content was analyzed by immunoblotting using Ab 39 serum as described in Materials and Methods.