Inactive Isoforms of trans-sialidase as a virulence factor from Trypanosoma cruzi

CARLA PASCUALE; JUAN M. BURGOS; JUAN MUCCI; ANDRES LANTOS; OSCAR CAMPETELLA; MARÍA SUSANA LEGUIZAMÓN

Villa General Belgrano

Simposio; 2nd Argentinian Symposium on Glycobiology; 2016

Trypanosoma cruzi depends on its sialylation tosurvive but is unable to synthesize sialic acid. It is scavenged from host?sglycoconjugates through a glycosyl-transfer reaction mediated by trans-sialidase(TS), a modified α(2,3)-sialidase expressed by trypomastigotes.TS activity is involved in the induction of strong alterations in the immunesystem, cells invasion, etc. TS family contain active (aTS) and an inactive(iTS) isoforms with a His342Tyr conserved mutation. T.cruzi is organized in 6 Discret Typing Units (UDT). We have reported that,in contrast to high-virulence strains (DTUs II, V and VI), lower-virulencestrains (DTUs I, III and IV) do not have the iTS encoding genes. Theacquisition of iTS genes may be associated with virulence. iTS protein retainsa lectin-like activity supporting their biologic relevance.Toanalyze it, we used the K-98 strain (UDTI). We have constructeda recombinant iTS-encoding gene where a 3xFLAG epitope was inserted (iTS/3xFLAG).This epitope allows us to identify iTS protein among aTS molecules that areantigenically undistinguishable. Epimastigotes were transfected anddifferentiated, and proteins expression was analyzed by immunofluoresce ontrypomastigotes (confocal and flow cytometry). In vitro assay showed that iTStransfected clones were able to infect significant more cells (P: 0.0162) and have higher intracelularreplications rate (P< 0.0001)than control parasites (aTS/3xFLAG, empty vector and WildType strain).