Allergic atopic disorders, such as asthma and rhinitis, result from genetic and environmental factors; there is a deregulated immune response, involving the T helper type 2 Everolimus molecular weight (Th2) cytokines interleukin (IL)-4, IL-5 and IL-13 and the Th1/proinflammatory cytokines interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Asthma is a chronic inflammatory disease with high morbidity and mortality, characterized by recurrent episodes of airway obstruction and wheezing [1,2]. Currently, more than 300 million people have asthma worldwide, and the numbers are increasing [3].

Human populations with high rates of parasitic helminth infections have a low prevalence of allergic disorders [4–7]. Also, treatment with anti-helminthic drugs leads to an increase in

the skin prick test response to aeroallergens [8,9]. Among helminths associated with protection against allergies, Schistosoma mansoni appears to induce particularly strong down-modulation of the inflammatory response that mediates atopic disorders [10]. In a 1-year follow-up study, we reported that asthmatics from a rural area endemic for schistosomiasis had fewer asthma symptoms when compared to those from a rural area in which there was no transmission of S. mansoni[11]. We also demonstrated that peripheral blood mononuclear cells (PBMC) from asthmatic individuals infected with S. mansoni produce higher levels of the anti-inflammatory GPCR Compound Library cytokine IL-10 and lower levels of IL-4 and IL-5 after restimulation in vitro with the allergen Dermatophagoides pteronyssinus antigen 1 buy Cetuximab (Der p1), compared to asthmatics without helminthic infections [12]. Although the immune responses in both allergies and S. mansoni infection are predominantly of the Th2 type, high IL-10 production has been found in S. mansoni infection [13,14], while there is reduced IL-10 production

in asthma patients [15]. A number of anti-inflammatory effects have been reported for IL-10; it appears to protect against allergy [12,16–19]. Support for this idea was provided by the observation that immunotherapy success is associated with increased IL-10 levels [20,21]. The induction of regulatory responses and disease prevention by helminths or their products has been observed not solely for allergic diseases, but also for autoimmune disorders [19,22–24]. Several S. mansoni antigens have been tested as vaccines to prevent S. mansoni infection and to prevent liver pathology, including Sm22·6, PIII and Sm29 [25,26]. We tested the potential of these three antigens to down-modulate the inflammatory response in an ovalbumin (OVA)-induced model of airway inflammation. The Sm22·6 antigen is a soluble protein associated with the tegument of S. mansoni, present throughout the life cycle of this helminth, with the exception of the egg stage [27]. Pacífico et al. found that recombinant Sm22·6 induces partial protection (34·5%) against experimental S. mansoni infection and also induces high levels of IL-10 production [28].