Characterization of LIC11207, a novel leptospiral protein that is recognized by human convalescent sera and prevents apoptosis of polymorphonuclear leukocytes

GABRIELA PRÊTRE, MARIA JOSE LAPPONI, MARINA V. ATZINGEN, MIRTA SCHATTNER, ANA L.T.O. NASCIMENTO, RICARDO M. GÓMEZ

MICROBIAL PATHOGENESIS

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 56 p. 21 - 28

0882-4010

We report the study of a predicted outer-membrane leptospiral protein encoded by the gene lic11207.This protein is conserved in several pathogenic leptospiral strains but is absent in the saprophyte Leptospirabiflexa. This putative outer-membrane protein has a domain of unknown function (DUF) 1565found in several phylogenetically diverse bacteria and in the archaeon Methanosarcina acetivorans. Thegene was cloned and expressed in Escherichia coli BL21 (SI) strain using the expression vector pDEST17.The 34 kDa recombinant protein was tagged with N-terminal hexahistidine and purified by metalchargedchromatography. The purified protein was used to assess: reactivity with human convalescentsera; in vivo expression; ability to activate endothelial cells (EC); and ability to modulate the apoptosis ofpolymorphonuclear cells (PMNs). The LIC11207 coding sequence was identified in vivo in the hamsterrenal tubules during experimental infection with Leptospira interrogans. The rLIC11207 showed significantantigenicity against human convalescent sera when compared with sera from healthy donors. Therecombinant protein did not alter the surface expression of E-selectin or intercellular adhesion molecule1 (ICAM-1) in EC and failed to induce the release of von Willebrand factor (vWF). Interestingly, rLIC11207delayed apoptosis of PMNs suggesting a possible role of this protein during the infection