rhamnosus CRL1505 significantly augmented the resistance of immunocompetent and immunocompromised malnourished mice to intestinal and respiratory pathogens such as Salmonella Typhimurium and Streptococcus GDC-0994 pneumoniae[10, 11]. In addition, we performed a randomized controlled trial in order to evaluate the effect of the probiotic yogurt containing L. rhamnosus CRL1505 on both gut and non-gut related illnesses among children [12].

We demonstrated that the CRL1505 strain Adriamycin improved mucosal immunity and reduced the incidence and severity of intestinal and respiratory infections. We registered that 34% of the children who consumed the probiotic yogurt showed some type of infectious event, while in the placebo group this value was higher reaching a 66% of them. Although we did not evaluate aetiology of intestinal and respiratory infections in the clinical study, previous evaluations have shown that viruses, such as rotavirus and respiratory syncytial virus, are the major pathogens, which cause

infectious diseases in children in northern Argentina [13, 14]. Therefore, our findings suggested that administration of L. rhamnosus CRL1505 may provide a potential intervention to prevent the course of common childhood viral infections. Some of the mechanisms by which L. rhamnosus CRL1505 exerts its immunomodulatory and antiviral properties have been elucidated [10, 11, 15]. We have recently showed the capacity of the CRL1505 strain to improve PU-H71 supplier the production of antiviral cytokines in the gut and the respiratory tract [10, 11, 15, 16]. However, the intestinal cells, cytokines and receptors involved in the immunoregulatory acetylcholine effect of this immunobiotic strain have not been fully characterized. Intestinal epithelial cells (IECs) are the first cells which encounter exogenous and endogenous as well as pathogenic and non-pathogenic microorganisms [17]. In addition, the gut of vertebrates is rich in antigen-presenting cells (APCs), such as

macrophages and dendritic cells (DCs), which are able to recognize foreign antigens or invading pathogens. The epithelium and APCs at the intestinal surfaces express a diverse range of Pattern Recognition Receptors (PRRs) capable of detecting viruses. Epithelial- and APCs-expressed PRRs include cell surface expressed C-type lectins (cell surface variants of the secreted collectins), intra- and extracellular toll-like receptors (TLR), the intracellular RNA-dependent protein kinase (PKR), retinoic acid–inducible gene I (RIG-I) like receptors (RLR) and nucleotide binding domain and leucine-rich repeat containing receptors (NLR) [18–20]. Upon recognition of double-stranded RNA (dsRNA) or its synthetic analogue poly(I:C), TLR3 and RIG-I trigger the activation of the transcription factors IRF-3, NF-kB, and AP-1, which in turn induce type I IFNs (especially IFN-β) and cytokine/chemokine synthesis. There is a growing interest in studying the swine immune system because of its similarities to the human immune system.