Helminths have a profound immunomodulatory effect upon the inductive and effector phases of inflammatory responses, including allergy. Several animal models of anaphylaxis have been established to investigate the mechanisms by which helminth infections or helminth-derived products interfere with the onset of allergic reactions. The focus of our studies was the immunosuppression induced by the intestinal roundworm Ascaris suum in the production of anaphylactic antibodies and the development of lung eosinophilic inflammation and hyperreactivity to its own allergens and to unrelated antigens. Thus, we identified a single protein affinity purified from the A. suum body extract, named PAS-1, which maintains all its immunosuppressive properties and promotes a significant increase in interleukin-10 production, an essential cytokine for the effectiveness of the suppressive mechanism. In addition, PAS-1 primes for regulatory T cells, which also mediate this mechanism. Therefore, this helminth molecule may be a promising target for therapeutic applications in allergic disorders.

It is known that in a part of the population, mainly among children, some are hypersensitive to soybean protein, although it is not yet completely elucidated which protein fraction is more immunogenic/ allergenic. The objective of the study was to compare the immunogenicity and allergenicity of the soy protein fractions. The 2S (conglycinin), 7S (β conglycinin) and 11S (glycinin) fractions were isolated from soy protein by affinity chromatography. These purified soy protein fractions were used as antigens for immunizing BALB/c mice to evaluate their immunogenicity by following the appearance of specific IgM and IgG antibodies in blood serum by ELISA. The allergenicity of these soy protein fractions was evaluated by the following approaches: i) the production of IgE antibodies against 2S, 7S and 11S soy protein fractions by BALBc mice in the anaphylactic cutaneous passive test (PCA), and ii) the production of IgG1 specific antibodies against the 7S fraction in BALB/c mice. The 7S and 11S fractions induced the formation of IgM and IgG antibodies. The PCA test showed that only the 7S fraction was allergenic leading to the production of IgE antibodies. Another evidence that reinforces the allergenicity of the 7S soy protein fraction is the presence of IgG1 specific antibodies reactive to this protein fraction in immunized mice. Our study shows that the 7S soy protein fraction is important to elicit allergic reactions in mice and may contribute to elucidate the allergenicity of soy-derived products. INTRODUCTIONAllergic reactions to foods result from heightened immunologic responses to glycoprotein components present in the foods and constitute a frequent health complaint (Metcalfe, 1991;Shah, Walker, 2002). Children and adults who develop such reactions are said to have a food hypersensitivity or food allergy that are terms proposed to define a reaction to food exposure causing objectively reproducible symptoms or signs at a dose A. L. Bittencourt, M. F. M. Soares, R. R. Pires, C. S. Honmoto, M. K. Tanaka, C. M. A. Jacob, D. S. P. Abdalla 598 tolerated by normal subjects (Crespo et al., 2004). The prevalence of food allergy in children appears to be increasing for reasons that are still poorly understood. It has been estimated that approximately 6% of young children and about 2% of the general population have food allergy, with the majority experiencing gastrointestinal symptoms (Sampson, 2003).A number of factors can affect the development of food allergy. One is the amount of a particular food that is ingested, which is influenced by diet and culture of a country. This can have a significant effect on the prevalence of a specific food allergy in that region. Examples of this are codfish allergy in Norway, rice and soy allergy in Japan, and peanut allergy in the U.S. Other factors involved in food allergies are the gut permeability, that has been considered to be a major factor in food allergy sensitization, and the food processing that can substantially modify food allergen content. Most food allergens are stable ...

Helminths secrete several molecules that can modulate the immune responses, favoring their evasion and perpetuate their survival in the host. These molecules interfere with antigen presentation, cell proliferation and activation, antibody production, cause cell death, and stimulate regulatory responses. Here, we focus on some helminth products and address their immunomodulatory effects in the host immune system and, also, we describe some anti-inflammatory properties of an Ascaris suum-derived immunomodulatory molecule, named PAS-1. This protein is a 200-kDa molecule isolated by affinity chromatography using MAIP-1 (monoclonal antibody which recognizes PAS-1), coupled to Sepharose 4B. It suppresses the inflammatory responses in murine models of delayed-type hypersensitivity, lung allergic inflammation and LPS-induced inflammation into air pouches. PAS-1 also stimulates the secretion of regulatory cytokines such as IL-10 and TGF-beta and primes IFN-gamma-secreting CD8+ and IL-10/ TGF-beta-secreting CD4+CD25+ cell clones that avoid the lung inflammation. Thus, this protein is a potent immunomodulatory component that may be used for therapeutic interventions in inflammatory diseases.