Study of irradiated bothropstoxin-1 with60Co gamma rays: immune system behavior

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.

Parasite survey in mouse and rat colonies of Brazilian laboratory animal houses kept under differents sanitary barrier conditions

A parasitological study was undertaken to determine the health status of 15 mouse and 10 rat colonies bred in 18 Brazilian laboratory animal houses maintained under different sanitary barrier conditions which supply animals for teaching, research purposes and manufacture of biological products for medical or veterinary use. Parasitological methods were used for diagnosis of mites, lices, helminthes and protozoan parasites. A questionnaire was answered by institutions with the intention to obtain information about the existence of barriers against infections and of regular sanitary monitoring program of their colonies. The questionnaire data show that the majority of the animal houses investigated do not possess an efficient sanitary barrier system able to keep animals under controlled health sanitary conditions. Ecto and endoparasite infections are widespread in the colonies and multiple infections were common in animals from most facilities investigated. The prevalences of parasites detected among the mouse and rat colonies of the laboratory animal houses investigated were: Myocoptes musculinus (46.6%), Myobia musculi (26.6%), Radfordia ensifera (13.3%), Syphacia obvelata (86.6%), Aspiculuris tetraptera (60.0%), Hymenolepis nana (53.3%), Spironucleus muris (80.0%), Tritrichomonas muris (80.0%), Giardia muris (66.0%), Entamoeba muris (20.0%), Eimeria sp. (13.3%), Hexamastix muris (26.6%), Poliplax spinulosa (30.0%), Poliplax serrata (10.0%), Radfordia ensifera (30.0%), Syphacia muris (80.0%), Hymenolepis nana (40.0%), Trichosomoides crassicauda (55.5%), Spironucleus muris (90.0%), Tritrichomonas muris (80.0%), Giardia muris (60.0%), Entamoeba muris (80.0%), Eimeria sp. (60.0%) and Hexamastix muris (60.0%).

Um estudo parasitológico foi realizado para verificar as condições de saúde de 15 colônias de camundongos e 10 colônias de ratos produzidos em 18 biotérios de instituições brasileiras que fornecem animais para ensino, pesquisa e produção de imunobiológicos de uso médico ou veterinário. Métodos parasitológicos foram utilizados para diagnóstico de ácaros, piolhos, helmintos e protozoários parasitos. Um questionário foi respondido pelas instituições com o intuito de obter informações sobre a existência de barreiras contra infecções e programa de fiscalização sanitária de suas colônias. Os dados do questionário mostram que a maioria dos biotérios analisados não possui um sistema de barreiras sanitárias eficiente capaz de manter animais sob condições sanitárias controladas. Infecções por ecto e endoparasitos são generalizadas nas colônias e a associação de infecções múltiplas foi comum na maioria dos animais dos biotérios analisados. A prevalência dos parasitos detectados entre as colônias de camundongos e de ratos investigadas foi: Myocoptes musculinus (46,6%), Myobia musculi (26,6%), Radfordia ensifera (13,3%), Syphacia obvelata (86,6%), Aspiculuris tetraptera (60,0%), Hymenolepis nana (53,3%), Spironucleus muris (80,0%), Tritrichomonas muris (80,0%), Giardia muris (66,0%), Entamoeba muris (20,0%), Eimeria sp. (13,3%), Hexamastix muris (26,6%), Poliplax spinulosa (30,0%), Poliplax serrata (10,0%), Radfordia ensifera (30,0%), Syphacia muris (80,0%), Hymenolepis nana (40,0%), Trichosomoides crassicauda (55,5%), Spironucleus muris (90,0%), Tritrichomonas muris (80,0%), Giardia muris (60,0%), Entamoeba muris (80,0%), Eimeria sp. (60,0%) e Hexamastix muris (60,0%).