Cytotoxicity of bacterial metabolic products, including listeriolysin O, on leukocyte targets.

Bacterial toxins can exhibit anticancer activities. Here we investigated the anticancer effects of the listeriolysin O toxin produced by Listeria monocytogenes. We found that supernatants of Listeria monocytogenes strains (wild type, 1189, and 1190) were cytotoxic to the Jurkat cell line and human peripheral blood mononuclear cells (PBMC) in a concentration-dependent manner. The supernatant of strain 1044, not producing listeriolysin O, was inactive. The supernatants of Listeria strains were also cytotoxic toward B cells of chronic leukemia patients, with no significant differences in activities between strains. We also tested supernatants of Bacillus subtilis strains BR1-90, BR1-S, and BR1-89 producing listeriolysin O. BR1-S and BR1-89 were cytotoxic to PBMC and to Jurkat cells, the latter being more sensitive to the supernatants. BR1-90 was not hemolytic or cytotoxic to PBMC, but was cytotoxic to Jurkat cells in the concentration range of 10-30%, suggesting that listeriolysin O is selectively effective against T cells. Overall, the response of human peripheral blood mononuclear and human leukemia cell lines to bacteria supernatants containing listeriolysin O depended on the bacteria strain, target cell type, and supernatant concentration.

[Potential role of the endothelium in pathogenesis of atherosclerosis]. / Potencjalna rola sródblonka naczyniowego w patogenezie miazdzycy.

The endothelium has an unique role at the interface of the blood and the tissues. It is involved in numerous homeostatic function, metabolism of lipoproteins, regulation of vascular tone and plays a role in the immune response. Due to its anatomic position, the endothelium is a primary target for injuries and atheromatosis risk factors. Hypertension, diabetes mellitus, hypercholesterolemia and smoking can alter endothelial function. A reduced release of endothelium-derived relaxing factors such as nitric oxide and an enhanced liberation of endothelium-derived contracting factors such as endothelin are common findings in the presence of atherosclerosis risk factors. These alterations of endothelial function are likely to contribute to the pathogenesis as well as progression and complications of atherosclerosis.