Resumen de Bacterial extract (OM-85) with human-equivalent doses does not inhibit the development of asthma in a murine model
A. Rodrigues, L.P. Gualdi, R.G. de Souza, M.H.M. Vargas, N.K. Nuñez, A.A. da Cunha, M.H. Jones, L.A. Pinto, R.T. Stein, Paulo Márcio Pitrez
Background OM-85 is an immunostimulant bacterial lysate, which has been proven effective in reducing the number of lower airways infections. We investigated the efficacy of the bacterial lysate OM-85 in the primary prevention of a murine model of asthma.
Methods In the first phase of our study the animals received doses of 0.5 μg, 5 μg and 50 μg of OM-85 through gavage for five days (days −10 to −6 of the protocol), 10 days prior to starting the sensitisation with ovalbumin (OVA), in order to evaluate the results of dose–response protocols. A single dose (5 μg) was then chosen in order to verify in detail the effect of OM-85 on the pulmonary allergic response. Total/differential cells count and cytokine levels (IL-4, IL-5, IL-13 and IFN-γ) from bronchoalveolar lavage fluid (BALF), OVA-specific IgE levels from serum, lung function and lung histopathological analysis were evaluated.
Results OM-85 did not reduce pulmonary eosinophilic response, regardless of the dose used. In the phase protocol using 5 μg/animal of OM-85, no difference was shown among the groups studied, including total cell and eosinophil counts in BALF, serum OVA-specific IgE, lung histopathologic findings and lung resistance. However, OM-85 decreased IL-5 and IL-13 levels in BALF.
Conclusions OM-85, administered in early life in mice in human-equivalent doses, does not inhibit the development of allergic pulmonary response in mice.
