Expression of different EPEC b-intimin fragments in lactic acid bacteria
Patricia C D Ferreiraa,b; Ivana B Campos a,b; Paulo L Hoa,b; Maria Leonor S Oliveiraa,b.
a Centro de Biotecnologia, Instituto Butantan, São Paulo, SP, Brazil ;
b Interunidades em Biotecnologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
Enteropathogenic Escherichia coli (EPEC) is a common etiological agent of severe diarrhea in infants, responsible for a large number of morbidity and mortality in developing countries. One of the virulence factors that promote the intimate adhesion of EPEC with enterocytes in the small intestine is intimin, a 94kDA outer membrane protein, essential for full virulence. As a result, activation of several signaling proteins in the host cells and rearrangement of the cytoskeletal lead to the formation of attaching and effacing lesions (A/E lesions), disrupting the membrane. Based on antigenic variations, intimins are classified in several subtypes that can be grouped into nine families; among them, b-intimin is one of the most frequently subtype found in clinical isolates.
Lactic acid bacteria are commensal microrganisms present in the gastrointestinal mucosa of health individuals that have been used as carriers for antigen presentation in different models. In this work different b-intimin fragments corresponding to the conserved region, to the variable region or to both regions were cloned into a vector based on the Lactococcus lactis P1 promoter. The recombinant vector was used for transformation of L. lactis and Lactobacillus casei. Intracellular expression of the different fragments in L. lactis and L. casei extracts was analyzed by Western-blot. The recombinant bacteria are now been tested for the induction of the immune system upon oral immunization of mice.
Supported by FAPESP, CNPq and Fundação Butantan.
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