Determination of the synthesis and uptake of alpha 2-macroglobulin by cultured human glioma cells.

Using immunological techniques, the synthesis of alpha 2-macroglobulin was studied in established cell lines derived from human glioblastomas multiforme. alpha 2-Macroglobulin was detected in cytoplasm and in the culture medium of the analyzed cell lines. Radioimmunoprecipitation revealed a protein with M(r) corresponding to alpha 2-macroglobulin in the medium conditioned by U-118MG and U-343MG cells. On the other hand, using immunoblot analysis, alpha 2-macroglobulin was detected in all of the analyzed lines. In immunofluorescence test, alpha 2-macroglobulin was determined also in all four cell lines, but with different staining pattern. Conditioned culture medium (CCM) of U-536MG cells with the lowest level of alpha 2-macroglobulin exerted the lowest mitogenic activity for human fibroblasts.