However, there is evidence in animal models indicating that oral administration of certain LAB can modulate allergic responses in the respiratory tract. These beneficial effects are strain specific and the observed efficacy is also likely influenced by the antigen sensitization and challenge protocols used in the animal model. The differential response to LAB in asthma models is further emphasized by at least one study demonstrating enhanced allergic airway inflammation following neonatal treatment Canadian Levitra online of mice with Lactobacillus casei. Although the exact mechanism(s) behind the antiallergic action of these bacteria remain obscure, several potential components of this response have been highlighted.
Asthma is a T lymphocyte-mediated inflammatory disease, and it has been suggested that the common mucosal immune system is involved, with activated T lymphocytes migrating from one mucosal site to another. In keeping with this, the beneficial effect of probiotic organisms appears to be strongly associated with changes in the balance of T-cell responses that lead to a reduction in Th2 activity. In particular, there is growing evidence from a range of model systems Health&Care Pharmacy that the ability to induce regulatory T cell (Treg) classes that attenuate both Th1 and Th2 responses may be a critical element in the antiinflammatory action of many probiotic organisms.
Tregs: Effectors of the Antiallergic Response?
Diverse populations of Tregs play an important role in regulating Th2 responses to allergen and maintaining functional tolerance. Tregs can be detected at sites of inflammation, and in many situations, their ability to migrate to and remain in inflamed tissue is important for their function in vivo. In rodent asthma models, CD4+CD25+Foxp3+ Tregs are recruited into the lungs and draining lymph nodes and can suppress allergen-induced airway eosinophilia, mucous hypersecretion, and hyperresponsiveness.
Attenuation of the allergic airway response following oral treatment of mice with Lactobacillus reuteri is associated with a significant increase in the proportion of functional CD4+CD25+Foxp3+ regulatory cells in the spleen and mediastinal lymph nodes.