ABSTRACT
Escherichia coli O157:H7, an emerging cause of food-borne disease with the occurrence of an estimated 20,000 illnesses and 250 deaths each year in the United States, has now been reported from several countries worldwide. Infections with this bacteria, which follows the ingestion of contaminated food by humans, causes bloody diarrhea, hemolytic uremic syndrome (HUS), and renal disease, that can have serious health implications. The source of food contamination is usually associated with animals, mainly cattle. Many cattle become infected early in life when they are exposed to an environment that is contaminated by other animals shedding the organisms in their feces. Detection of E. coli O157:H7 in feces or contaminated food samples requires tests with high sensitivity, which is increased by the use of monoclonal antibodies. However, the production of concentrated monoclonal antibodies in ascites raises animal welfare concerns, and can be expensive. In this study, single chain of variable fragment (scFv) molecules were developed from hybridoma clones that produce immunoglobulins specific for the LPS and flagella antigen of E. coli O157:H7 using phage display technology. The reactivity of the soluble scFv for their respective antigens was preserved in ELISA and by partial inhibition of bacterial agglutination with polyclonal antiserum. Furthermore, the scFv were able to capture E. coli O157:H7 bacteria demonstrating their potential use in diagnostic assays.
Subject(s)
Animals , Antibodies, Bacterial/genetics , Base Sequence , DNA, Complementary/biosynthesis , Enzyme-Linked Immunosorbent Assay , Escherichia coli O157/immunology , Flagella/immunology , Hybridomas/immunology , Lipopolysaccharides/immunology , Mice , Recombinant Proteins/biosynthesisABSTRACT
Extractos crudos de especímenes de Culex quinquefasciatus (Say), Boophilus microplus (Canestrini), Amblyomma cajennense (Fabricius) y Blatella germanica (L) fueron analizados por medio de electroforesis en gel de poliacrilamida, para detectar actividad de B esterasas. Los extractos crudos de una cepa resistente a organofosforados de B. microplus presentaron diferencias en el patrón electroforético cuando fue comparado con una cepa susceptible a organofosforados de larvas de B. microplus. El extracto crudo de Cx. quinquefasciatus cepa florida presentó una banda de marcada actividad. En la muestra de A. cajennense se encontró una banda de diferente pero molecular; y en el extracto crudo de Blatella germanica se localizaron dos bandas de diferente peso molecular. Se utilizaron suero y eritrocitos de origen bovino como testigos.