Synthesis and release of plasminogen activator by lymphoid cell lines of malignant origin and its effect on lymphocyte cytotoxicity.
Lymphoid B, T. Null and plasma cell lines of malignant origin were evaluated for their ability to produce plasminogen activator (PA) in the 125I-fibrinolysis assay. These cell lines produced PA at varying extent. PA was detected in cell-free conditioned medium as well as in cell lysates. The fibrinolysis due to PA was dependent on the presence of plasminogen in the medium. PA purified by affinity chromatography not only abrogated cytotoxicity of peripheral blood lymphocytes significantly, but also the lysis of autologous EBV-transformed cells by in vitro generated cytotoxic lymphocytes. These results indicate that PA produced by malignant cells could inhibit host cellular immunity, thus providing the tumor cells with an escape mechanism from host defences.
Sundar
S K
SK
Bergeron
J
J
Menezes
J
J
D002051:Burkitt Lymphoma / Q000378:metabolism*; D002460:Cell Line; D002472:Cell Transformation, Viral; D003470:Culture Media; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D004854:Herpesvirus 4, Human; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D010960:Plasminogen Activators / Q000378:metabolism* / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects*
D003470:Culture Media; D010960:Plasminogen Activators