Augmentation of Macrophage Phagocytic Activity by Cell-Free Extracts of Selected Lactic Acid-Producing Bacteria

Abstract

Oral and intraperitoneal administration of lactic acid-producing bacteria can significantly augment the immune response in murine models; however, the immunopotentiating effects in these studies differ significantly. Murine macrophagelike cell line J774 was cultured in the presence of cell-free extracts of Lactobacillus acidophilus and Bifidobacterium longum, and the effect on macrophage function was evaluated by measurement of synthesis of selected enzymes and their ability to take up either acrylamide particles or live Salmonella typhimurium. Lysozyme activity of J774 cells was significantly decreased by cell-free extracts of B. longum, but not of L. acidophilus, whereas extracts of both strains induced morphological changes and significantly enhanced phagocytosis of inert particles or viable Salmonella. Whole cell extracts of lactic acid-producing bacteria are therefore capable of altering macrophage function in a strain-dependent manner.

Lactic acid bacteria and the human gastrointestinal tract

“…Other studies have demonstrated that lactic acid bacteria stimulate macrophage phagocytosis of viable Salmonella (Hatcher & Lambrecht, 1993), enhance IgA production in intestinal secretions (Perdigon et al, 1990), produce an antimicrobial substance (Shahani & Ayebo, 1980;Silvia et al, 1987), inhibit cell attachment and cell invasion by enterovirulent bacteria (Bernet et al, 1994), and decrease intestinal permeability for macromolecules during rotavirus induced diarrhoea (Isolauri et al, 1993).…”

Augmentation of antimicrobial activity of conventional antibiotics by cell-free extract of L. plantarum

“…20 Studies have also shown that CFSs and/or extracts from lactic acid producing bacteria may activate macrophages in-vitro thereby resulting in augmented phagocytic activity. 21,22 These findings can prove to be vital in rejuvenation of ampicillin therapy against Salmonella, as it is no longer used because of worldwide emergence of ampicillin-resistant Salmonella strains.…”

Protection by Lactobacillus acidophilus UFV-H2B20 against experimental oral infection with Salmonella enterica subsp. enterica Ser. Typhimurium in gnotobiotic and conventional mice

“…The potential mechanisms by which probiotic agents might exert their protective or therapeutic effect against infections include competition for nutrients or adhesion receptors (1), production of inhibitory metabolites or antimicrobial compounds against pathogens (6), immunomodulation (5), and modulation of toxin production or action (2,3). The first three mechanisms were suggested for lactobacilli.…”