Superoxide production by phagocytes in myeloid Graffi tumor-bearing hamsters.

A progressive suppression of the phagocytic ability of peritoneal macrophages and polymorphonuclears (PMNs) in hamsters with transplanted myeloid tumors was previously established. The i.p. application of Cu/Zn SOD, isolated from the fungal strain Humicola lutea (HLSOD) (2 injections before and 5 injections after tumor transplantation) induced the mean survival time of the animals as well as a temporally stimulating action on the macrophage and PMNs phagocyting indices. In the present work, the superoxide production of peritoneal macrophages and PMNs during 30 days of tumor progression was followed. Effects of the application of HLSOD in an optimal protective dose on the superoxide production in peritoneal macrophages and blood PMNs were examined. The spontaneous and phorbol-myristate acetate (PMA)-inducible O2- production in both types of phagocytes was 4-5-fold increased in tumor-bearing hamsters (TBH), as compared to the controls, at day 14 after tumor transplantation (the day of tumor appearance in transplanted animals). Furthermore, O2- production was also similar to the control values for the following days of observation. HLSOD treatment of TBH induced a normalization of superoxide production in macrophages and PMNs. Therefore, the established decrease of superoxide anions in phagocyting cells of TBH indicates possible effects of HLSOD on the host antioxidant defense.

Effect of Escherichia coli L-form cytoplasmic membranes on the interaction between macrophages and Lewis lung carcinoma cells: scanning electron microscopy.

Scanning electron microscopy (SEM) investigations on the interactions between peritoneal macrophages from Lewis lung carcinoma (LLC)-bearing mice and LLC tumour cells during 21 days after tumour implantation were carried out. The action of lipopolysaccharide (LPS)-containing cytoplasmic membranes (CM), from the stable protoplast type L-form of Escherichia coli, on the activity of in vitro phagocytosis was studied; CM induced a continuous increase in macrophage numbers. Activation of macrophage surfaces in healthy and tumour-bearing mice was established. Lamelipods, pseudopods and migration fringes 14 days after CM application were seen. Crater-like cavities deeply in the macrophage cells as well as adherent or prominent engulfed tumour cells within macrophages were observed during in vitro interaction with LLC cells. Macrophages from tumour-bearing mice without CM treatment showed less activation evaluated by SEM during earlier stages of tumour growth. The SEM investigation proved the temporary stimulating effect of E. coli L-form CM on the cell surface activation of peritoneal macrophages in healthy and LLC-bearing mice.