immunology of infectious and parasitic diseases - XXXVII Congress ...

OspC1 AND OspF: VIRULENCE FACTORS INVOLVED IN THE INHIBITION OF
INTESTINAL INFLAMMATORY RESPONSE CAUSED BY ENTEROINVASIVE
Escherichia coli
RENÉE DE NAZARÉ OLIVEIRA DA SILVA (1) , LUCAS GONÇALVES FERREIRA (1) ,
FRANCIELE HINTERHOLZ KNEBEL (1) AND MARINA BAQUERIZO MARTINEZ (1)
(1) Department of Clinical and Toxixological Analysis, Faculty of Pharnaceutical
Sciences, University of São Paulo.
Introduction and objective: Enteroinvasive E. coli (EIEC) is one etiological agent of
bacillary dysentery, which is characterized by the colonic epithelium destruction
caused by the inflammatory response induced by bacteria invasion in mucosa
Strains of EIEC are biochemical, genetic and pathogenic similar to Shigella spp. The
pathogenecity of EIEC and Shigella depend of the plasmid pInv, which has the
genes necessary for bacterial colonization in the intestinal mucosa. Recently, it was
demonstrated that the plasmid genes ospC1, ospG and ospF of S. flexneri are
involved in inhibition of the inflammatory response in intestinal epithelial cells, which
is an important factor in the initiation of bacterial colonization and production of
disease. As EIEC has showed less severe disease than Shigella, we evaluated the
transcription of these plasmid genes and inflammatory response modulated by this
microorganism in the intestinal epithelial cell Caco-2. Metodology and Results: The
Caco-2 cells were infected in different times with many serotypes of EIEC and S.
flexneri M90T strain. The data about invasiveness and survival of bacteria, bacterial
genes expression, and chemokine IL-8 were obtained by CFU, RT-PCR, and ELISA,
respectively. The statistical significance was evaluated by two-way ANOVA. All EIEC
serotypes studied expressed the genes ospC1, ospG and ospF, suggesting the
involvement of them in modulating of the immune response induced by these
microorganisms. There were no differences in the invasion the enterocytes among
EIEC serotypes (p>0.05). However, we observed a difference in the transcription of
those genes and production of IL-8. The EIEC serotypes O29:H- and O167:H-
showed a low transcription of genes ospC1 and ospF, and an significant increase in
IL-8 release compared with other serotypes (p