PAS‐1, a protein affinity purified from Ascaris suum worms, maintains the ability to modulate the immune response to a bystander antigen

• Published in: Immunology and cell biology 2006-04, Vol.84 (2), p.138-144
• Main Authors: Oshiro, Telma M, Enobe, Cristina S, Araújo, Cláudia A, Macedo, Mahasti S, Macedo‐Soares, Maria Fernanda
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Helminth - immunology; Antibody Formation - immunology; antibody response; Antigens, Helminth - chemistry; Antigens, Helminth - immunology; Antigens, Helminth - isolation & purification; Ascariasis - immunology; Ascaris suum; Ascaris suum - chemistry; Ascaris suum - immunology; Bystander Effect - immunology; cytokine; Dose-Response Relationship, Immunologic; Down-Regulation - immunology; Female; Helminth Proteins - chemistry; Helminth Proteins - immunology; Helminth Proteins - isolation & purification; Immune Tolerance; immunosuppression; Interleukin-10 - immunology; Interleukin-4 - immunology; Male; Mice; Mice, Inbred BALB C; Th1 Cells - immunology; Th2 Cells - immunology
• ISSN: 0818-9641; 1440-1711
• DOI: 10.1111/j.1440-1711.2005.01404.x

Helminth infections and parasite components have potent immunomodulatory effects on a host's immune system. In the present study, we investigated the effect of PAS‐1, a protein component of Ascaris suum adult worms recognized by a monoclonal antibody (MAIP‐1), on humoral and cell‐mediated responses to a bystander antigen (ovalbumin [OVA]). MAIP‐1 recognized only one of the three polypeptide chains of PAS‐1, but neutralized the suppressive effect of the whole worm extract on OVA‐specific antibody production. PAS‐1 inhibited antibody production against a T‐cell‐dependent, but not a T‐cell‐independent, antigen in a dose‐dependent way. IgM, IgG1, IgG2b, and also IgE and anaphylactic IgG1 levels were downregulated. In addition, PAS‐1 inhibited OVA‐specific delayed type hypersensitivity reactions in the footpad of mice, showing a potent immunosuppressive activity on both Th1 and Th2 responses that seems to be mediated by the induction of large amounts of IL‐10 and IL‐4. Indeed, PAS‐1‐specific spleen cells secreted sevenfold more IL‐10 and threefold more IL‐4 than OVA‐specific cells in response to in vitro restimulation with the respective antigens. In conclusion, we showed that PAS‐1, a single protein component from A. suum, maintains all its immunosuppressive properties.