amphotericin-b and ubenimex

The following aminopeptidase (AP) activities were found to be associated with the surface of mouse spleen cells: Leu-AP (138 pmol/10(5) cells X minute) and AP-B (16 pmol/10(5) cells X minute with Lys-beta-naphthylamide as substrate and 21 pmol/10(5) cells X minute with Arg-beta-naphthylamide substrate); AP-A activity was not detected by the assay system applied. The immunoactive peptide bestatin inhibited the Leu-AP, while AP-B activity decreased in the presence of both arphamenines A and B and bestatin. No effects on these enzymes were caused by amastatin (an AP-A inhibitor), FK-156, FK-565 and Bu-2743E; the latter peptide turned out to be not an inhibitor of cell surface associated microsomal Leu-AP but an inhibitor of cytosolic Leu-AP. The immunoactive peptides bestatin, arphamenines A and B, and amastatin increased [3H]thymidine incorporation into spleen cells containing lymphocytes and macrophages. These mitogenic actions were not observed when macrophages were removed from the cultures or the cells had been stimulated with ConA or LPS. The lactoyl- and heptanoyl peptides FK-156 and FK-565 caused a mitogenic action on lymphocytes independently of the presence of macrophages. The inhibitor of cytosolic Leu-AP did not change the incorporation into lymphocytes.

Topics: Adjuvants, Immunologic; Amino Acids, Diamino; Aminopeptidases; Amphotericin B; Animals; Anti-Bacterial Agents; Diaminopimelic Acid; Dipeptides; Glutamyl Aminopeptidase; Leucine; Leucyl Aminopeptidase; Lymphocyte Activation; Lymphocytes; Male; Mice; Mitogens; Oligopeptides; Peptides; Spleen

The interactions with tumor target cells of resident and BCG-activated murine peritoneal macrophages (M phi) as well as of BCG-activated M phi additionally stimulated by a lymphokine-like factor were investigated in order to get some insight into the cytolytic process mediated by activated M phi. The lymphokine-like factor enhancing the cytotoxicity of BCG-activated M phi (MCF) was isolated and partially purified from cell-free fluid of rat Zajdela ascites hepatoma. M phi cytotoxicity was determined by a modified 51Cr release assay. Scanning and transmission electron microscopic findings suggested a two-step mechanism of target cell lysis: a first step of specific attachment of processes of M phi on the target cell surface and a second step with transport of lysosome-like vesicles to the target cells obviously with liberation of these vesicles in the immediate vicinity of target cells resulting in a local accumulation of cytolytic substances. This interpretation was supported by findings after treatment of interacting effector and target cells with amphotericin B and bestatin which substances were modifying M phi cytotoxicity. MCF caused only an augmentation of M phi cytotoxicity without qualitative differences to the cytolytic action of merely BCG-activated M phi.

Topics: Adjuvants, Immunologic; Amphotericin B; Animals; BCG Vaccine; Cytotoxicity, Immunologic; Female; Leucine; Macrophage Activation; Macrophages; Mice; Mice, Inbred DBA; Mice, Inbred Strains; Microscopy, Electron; Microscopy, Electron, Scanning; Neoplasm Transplantation; Pseudopodia; Sarcoma, Experimental