NANCI DO NASCIMENTO
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Artigo IPEN-doc 09897 Effects of gamma rays on the immunogenicity (IgG types) of ovalbumin2004 - 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 crotamine2004 - CASARE, M.S.; BAPTISTA, J.A.; SPENCER, P.J.; NASCIMENTO, N.Artigo IPEN-doc 11621 Study of gamma-radiation effects on crotamine and crotoxin2006 - 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 14083 Study of irradiated bothropstoxin-1 with sup(6)Co gamma rays: immune system behavior2009 - CAPRONI, P.; BAPTISTA, J.A.; ALMEIDA, T.L. de; PASSOS, L.A.C.; 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 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. 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 investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.