In vitro proinflammatory response mediated by Shigella sonnei virulence plasmid spontaneous mutant

CORTÉS, LE; SERRADELL, MA; DE URRAZA, PJ

Villa Carlos Paz, Córdoba

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

The pathogenesis of Shigella is focus in the capacity to invade intestinal epithelial cells, replicate and escape from the infected enterocytes triggering a proinflammatory immune response sense by Nod1 intracellular receptors. For this purpose Shigella have a virulence plasmid of~220 kb (pINV) that encodes essential products, some of them are included in ipaBCDA operon. In previous works we have shown the absence of amplification and expression of the genes of ipaBCDA operon in Shigella sonnei clinical isolates by PCR and western blot. Moreover, these ipaBCDA negative mutants showed ability to invade Hep-2 and Caco-2. In this work the ability of S. sonnei ipaBCDA-to induce theexpression of CCL20 and IL-8 as a measure of the proinflammatory response in Caco-2 cells was studied. Caco-2 cells containing ccl20:luc reporter construction were incubated with heat killed S. sonnei IpaBCDA- and S. flexneri ipaBCDA+ clinical isolates, and assayed for luciferase activity. In a second approximation Real Time PCR was performed using specific primers for ccl20, il-8 and actin B as housekeeping gene. Despite of the absence of virulence proteins, known as necessary for invasive phenotype and Nod1 proinflammatory pathway, we have found by both methods similarexpression pattern of chemokines, CCL20 and IL-8, induced either by S. sonnei ipaBCDA- or S. Flexneri.