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  • Resumo IPEN-doc 13668
    Immunological properties of sup(60)Co gamma rays irradiated bothropstoxin-I
    2008 - BAPTISTA, J.A.; VIEIRA, D.P.; GALISTEO JUNIOR, A.J.; CAPRONI, P.; CASARE, M.; ANDRADE JUNIOR, H.F.; SPENCER, P.J.; NASCIMENTO, N.
  • Artigo IPEN-doc 09898
    Effects of gamma rays on the immunogenicity (IgG types) of ovalbumin
    2003 - BAPTISTA, J.A.; SPENCER, P.J.; AROEIRA, L.G.S.; CASARE, M.S.; NASCIMENTO, N.
    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with gamma rays, yielding toxoids with good immunogenicity. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we used ovalbumin as a model to investigate possible immunogenic differences between native and irradiated proteins. Native ovalbumin (2mg/ml in 150mM NaCl) was irradiated with 2kGy of 60Co gamma rays with a 570Gy/h dose rate. B10.PL mice (n=5) were then immunized with either the native or the irradiated protein. After three immunizations, serum samples were collected and the antibody titers and isotypes were determined by enzyme-linked immunoadsorbant assay. Our data indicate that no difference could be noticed when the antibody titers of the two groups were compared. However, the isotyping assays indicates that the native protein induced high levels of IgG1, while its irradiated counterpart displayed mostly IgG2b antibodies. These data suggest that after irradiation, an antigen known to induce a Th2 response, is able to switch the immune system towards a Th1 pattern.
  • Artigo IPEN-doc 09895
    Effects of sup(60)Co radiation on the molecular structure of crotamine
    2003 - CASARE, M.S.; BAPTISTA, J.A.; SPENCER, P.J.; NASCIMENTO, N.
  • Artigo IPEN-doc 09897
    Effects of gamma rays on the immunogenicity (IgG types) of ovalbumin
    2004 - BAPTISTA, J.A.; SPENCER, P.J.; AROEIRA, L.G.S.; CASARE, M.S.; NASCIMENTO, N.
  • Artigo IPEN-doc 09896
    Effects of sup(60)Co radiation on the molecular structure of crotamine
    2004 - CASARE, M.S.; BAPTISTA, J.A.; SPENCER, P.J.; NASCIMENTO, N.
  • Artigo IPEN-doc 11621
    Study of gamma-radiation effects on crotamine and crotoxin
    2006 - CASARE, M.S.; SPENCER, P.; CAMPOS, L.A.; NASCIMENTO, N.
    Crotoxin is a 23 kDa neurotoxin from Crotalus durissus terrificus and is composed of a 9 kDa acidic subunit (crotapotin) and a 14 kDa basic subunit (phospholipase A2). Crotamine is 4882 Da, basic polypeptide with myotoxic activity. These toxins, when submitted to gamma-rays, in aqueous solution, present structural modifications, preserving their immunogenic properties. In the present work, we investigated some structural modifications on both crotoxin and crotamine after gamma-radiation using various doses, in the presence or not of "scavenger" substances. Our results indicate that irradiation leads to progressive changes in the structure of the toxin, which could explain the lower toxicity observed.
  • Artigo IPEN-doc 14173
    Immunological properties of sup(60)Co gamma-rays irradiated bothropstoxin-I
    2009 - BAPTISTA, J.A.; VIEIRA, D.P.; GALISTEO JUNIOR, A.J.; CAPRONI, P.; CASARE, M.; ANDRADE JUNIOR, H.F. de; SPENCER, P.J.; NASCIMENTO, N.