Cystatins of has been shown to increase the production of IFN- and IL-12 by human peripheral blood mononuclear cells [30], and they can inhibit cathepsin B, leading to enhanced expression of Th1 cells [31]. in IFN- knockout mice, and the Th2 responses in these mice were as strong as those in wild-type mice sensitized with ovalbumin. The crude extract of also suppressed the airway inflammation associated with established asthma. This study provides new insights into immune modulation by the crude extract, which suppressed airway inflammation in mice not only during the development of asthma but also after its establishment by skewing allergen-induced Th2 responses to Th1 responses. Introduction The incidence of allergic diseases such as asthma, allergic rhinitis and eczema has continuously increased during the recent decades, especially in developed countries or urban areas of developing countries where helminth infections Briciclib are rare or under control [1], [2]. Although allergic diseases and helminth infections both illicit Th2 responses, helminths have been known to provoke anti-inflammatory responses rather than allergic reactions in humans and animals [1], [3], [4]. A significant amount of epidemiological evidence from human field studies has suggested the presence of an inverse relationship between helminth infections and asthma and allergic sensitization [5]C[8]. However, other studies have reported no protective effects or enhanced allergic sensitization in individuals infected with parasites [9]C[11]. Experimental studies using animal models have also shown varying effects of parasite contamination on the protection of the host against airway inflammation and allergic disease [1]. Contamination with or in mice suppressed experimental airway inflammation [12], [13], whereas contamination exacerbated the allergic responses to ovalbumin (OVA) in mice [14]. contamination in mice caused different responses to an allergen depending on the production of eggs within the host; chronic contamination with Briciclib male and female worms aggravated OVA-induced airway hyperresponsiveness (AHR), but experimental contamination with male schistosomes only guarded mice from AHR [15]. This conflicting association between helminth infections and Rcan1 allergic diseases may be the result of several factors, including the species of parasite, the worm burden, the frequency and period of contamination and the timing of contamination [9], [14]. Recently, helminth therapy has been used to ameliorate allergic or inflammatory diseases [16]C[19], and studies have reported promising outcomes, especially in the treatment of inflammatory bowel disease [18], [19]. However, the use of helminths for the treatment of inflammatory diseases has several potential side effects, including iatrogenic contamination, general immune suppression, anaphylactic or atopic reactions and cross-reactivity with allergens [1]. Additional limitations of helminth therapy may include the difficulty of preparing specific pathogen-free eggs or larvae, the high cost Briciclib of the therapy and Briciclib poor patient compliance with consuming eggs or worms as therapeutic brokers. An alternative solution to overcome these prospective problems would be the use of helminth-derived products that have anti-allergic or anti-inflammatory properties [16]. Several helminth-derived products that are known to alter the immune responses of the host and to have therapeutic potential for inflammatory diseases have been suggested based on data from animal models of human diseases [1], [16], [20]. Asthma is usually a complex disorder associated with Th2 immune responses directed to allergens and is characterized by airway inflammation, AHR, variable airflow obstruction and airway remodeling [21]C[23]. The mainstay of asthma treatment consists of inhaled or oral corticosteroids and long-acting 2-adrenoceptor agonists; however, these treatments are not curative, and symptoms return soon after treatment termination [21]. Reducing or eliminating allergen-specific Th2 responses in the early stage of asthma may lead to disease remission, which suggests that this may be one potential strategy for the development of new drugs [21]. This study was undertaken to evaluate the effects of a crude extract of (CEC) on the development of OVA-induced asthma in a murine model. We found that CEC strongly suppressed airway inflammation not only during the development of asthma but also after the establishment of asthma in mice and that IFN- was the most important cytokine in the CEC-mediated suppression of asthma. This study provides new insights for understanding immune modulation by crude extract The N2 strain was grown in media supplemented with OP50 as a food source. The worms were incubated at room temperature for six days. Adult worms were isolated, washed three times in sterile distilled water and.