Fig. 2. KS SLK and KS IMM cells express VEGF isoforms and vß3 integrin receptor. KS SLK and KS IMM produced 1520 and 1150 pg/ml of VEGF, respectively (see "Results"). Given this similar production, we selected the KS SLK cells to identify VEGF isoforms. A, KS SLK cells were metabolically labeled with [S35]methionine and [S35]cysteine. Cell extracts and supernatants were combined and immunoprecipitated with anti-VEGF polyclonal antibodies as described in "Patients and Methods." KS SLK cells showed three bands of Mr 16,000, 18,000, and 24,000 (arrows) that were absent in the immunoprecipitant of antibody preabsorbed with immunogen VEGF peptide. Lane +, immunoprecipitant using anti-VEGF antibody that has been preabsorbed with immunizing peptide. Lane -, labeled proteins immunoprecipitated with anti-VEGF-antibody alone. B and C, KS SLK and KS IMM cells express the vß3 integrin receptor. One million cells were fixed and labeled with anti-vß3 integrin antibody and then examined by flow cytometry. B, the boldface tracing on the right represents the signal with anti-vß3 integrin antibody of KS SLK cells; the tracing on the left represents the signal of the control isotype antibody. C, anti-vß3 integrin antibody staining of KS IMM cells using similar methods. D, KS SLK, KS IMM, and dermal microvascular endothelial cells (DMEC) expressed the ß3 subunit of vitronectin receptor (arrow), which is expressed at lower levels in peripheral blood lymphocytes (PBL).