CONICET | Buscador de Institutos y Recursos Humanos

Lactic acid bacteria (LAB) are technologically and commercially important and have various beneficial effects on the improvement of health. In last two decades, studies on the physiological function of probiotic bacteria, mainly LAB, have been rapidly progressed in the world. In many studies, whole cells, including live and heatkilled cells, cell wall and cytoplasmic fractions of LAB have been demonstrated to exert various biological functions. Numerous studies have demonstrated that probiotic LAB can exert their beneficial effect on the host through their immunomudulatory activity. Probiotics are thought to regulate intestinal immunity by contact and stimulation of immunocompetent cells in the gastrointestinal tract and induction of cytokine production. Although most research concerning probiotic-mediated enhanced immune protection is focused on gastrointestinal tract pathogens, a few recent studies centred on whether probiotic LAB might sufficiently stimulate the common mucosal immune system to provide protection to other mucosal sites as well. In this sense, it has been reported that probiotics are able to improve the immune response against respiratory pathogens. The innate immune system represents the first line of the defensive mechanisms protecting from invading pathogens and relays signals to the adaptive immune system. In recent years, it has been demosntrated that the immunomodulatory effect of probiotic is related to their capacity to impact n innate immune cells. In this review we will give an overview about the mechanisms ssociated to the effects of probiotic LAB on the modulation of innate immunity and the impact on host response to infections. We will review the progress made so far in local innate immunity (gastrointestinal) and distant mucosal sites such as the respiratory tract.