Stimulation of Immunoprotective Mechanisms by OM-85 BV

Abstract

OM-85 BV, an immunomodulating preparation containing extracts from eight commonly pathogenic bacterial species, has been used with success as an oral adjuvant in the prevention of respiratory tract infections. Results from in vitro and in vivo experiments suggest various mechanisms that can underlie this beneficial effect. Thus, exposure of murine macrophages in vitro to OM-85 BV led to stimulation of biochemical and functional parameters associated with the disposal of microorganisms and tumor cells. Similarly, blood-derived human phagocytes were stimulated to express adhesion molecules (LFA-1, MAC-1, pl50,95, ICAM-1), to synthesize TNF-α and IL-2, and to develop a natural killer activity. These in vitro functions are reflected in the activation of immunological processes in vivo following administration of OM-85 BV per os. Oral treatment of mice and rabbits increased the capacity of the animals to clear bacteria from the blood, an effect that could be ascribed to enhanced functional activity of polymorphonuclear leukocytes. Administration of OM-85 BV per os also led to enhanced salivary IgA levels in man, and in gut and lung secretions in animals. Stimulation of migration and the beneficial effects of OM-85 BV correlated with phagocytosis-induced superoxide production in human bronchoalveolar lavage cells from orally treated individuals. Finally, injection of OM-85 BV was shown to enhance recovery from irradiation in animals, presumably by improving hemopoietic recovery. These findings indicate that OM-85 BV is capable of stimulating both cellular and humoral components of the immune response. In particular, administration per os promotes immune protective mechanisms active at the level of mucosal surfaces, thus providing a rationale for the oral prevention of acute exacerbations of chronic and recurrent respiratory tract infections using bacteria-derived immunomodulating agents.

The bacterial extract OM-85 BV protects mice against Influenza and Salmonella infection

“…We and other groups also previously demonstrated the in vitro unspecific macrophage, monocyte and granulocyte activation by OM-85 BV as well as the activation of dendritic cells [10][11][12][13][14][15][16][17] and showed that the bacterial extract acts mainly, but not exclusively via the TLR-4 cascade [W.G. Bessler et al, in preparation].…”

“…Bacterial extracts have been shown in vitro to enhance the production of tumor necrosis factor alpha (TNFalpha), interleukins, and IFN-gamma. The extract stimulates the phagocytic and metabolic activity of macrophages, activates natural killer cells, and upregulates adhesion molecules [10][11][12][13][14][15][16]. Dendritic cells activated with OM-85 BV exhibit an enhanced T cell stimulatory activity [17].…”

Bacterial Extracts as Immunomodulators for the Prevention of Recurrent Respiratory Infections in Children

“…Several randomized clinical trials have shown that OM-85 can reduce the number of ARTI of 25-50% in adults and children [16][17][18][19][20][21]. However, these studies were designed to demonstrate the preventive effect of OM-85 on AIRT in children with recurrent infections defined by the presence of diagnostic symptoms for at least 48 hours.…”

Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack

“…Finally, in toddlers aged 6-18 months, a clinical trial is ongoing to assess the preventive effect of OM-85V on the onset of first wheeze episode related to lower respiratory tract infection during a 3 years observational period [163]. Regarding the mechanisms of action, prevention of acute respiratory infections was not induced by purified LPS or bacterial DNA, suggesting that other PAMP contained in bacterial lysates would activate innate immunity and lead to promotion of type 1 inflammation by DC [164][165][166].…”