Antiinfluenza virus activity of a bacteriocin produced by Lactobacillus delbrueckii

A novel antibacterial substance produced by Lactobacillus delbrueckii has b een isolated and characterized (1). The inhibitory agent corresponded to th e criteria for bacteriocins. It was active against lactic acid bacteria (LA B) species and several food-borne pathogens. The cell-free supernatant was purified by HPLC gel-filtration. Three preparations at different purificati on steps were tested for activity on the reproduction of influenza virus A/ chicken/ Germany, strain Weybridge (H7N7) and strain Restock (H7N1) in cell cultures of chicken embryo fibroblasts (CEF). The inhibitory effect was sh own to be highly selective and specific. Expression of viral glycoproteins hemagglutinin, neuraminidase, and nucleoprotein on the surface of infected cells, virus-induced cytopathic effect, infectious virus yield, and hemaggl utinin production were all reduced at nontoxic concentrations of the crude preparation (B1). B1 did not protect cells from infection, did not affect a dsorption, and slightly inhibited viral penetration into infected cells. Th e purification did not enhance the cellular toxicity and increased about 87 0-fold the virus-inhibitory activity. No inactivating effect on extracellul ar virus was found.