Infection by Trypanosoma cruzi metacyclic forms deficient in gp82 but expressing a related surface molecule, gp30
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2003-11
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Trypanosoma cruzi metacyclic trypomastigotes invade and replicate in the gastric mucosal epithelium after
oral infection. In this study we analyzed the process of infection by T. cruzi isolates deficient in the expression
of gp82, the metacyclic stage-specific surface glycoprotein implicated in target cell entry in vitro and in
promoting mucosal infection in mice after oral challenge. Mice infected by the oral route with metacyclic forms
of gp82-deficient isolate 569 or 588 developed patent parasitemia but at greatly reduced levels compared to
those infected with the gp82-expressing isolate CL. Metacyclic forms of both isolates expressed gp30, a surface
glycoprotein detectable by monoclonal antibody (MAb) 3F6 directed to gp82. Otherwise, the gp82-deficient
isolates displayed a surface profile similar to that of the CL isolate and also entered epithelial HeLa cells in
a manner inhibitable by MAb 3F6 and dependent on the parasite signal transduction that involved the
activation of protein tyrosine kinase and Ca2 mobilization from thapsigargin-sensitive stores. Like gp82, gp30
triggered the host cell Ca2 response required for parasite internalization. Purified gp30 and the recombinant
gp82 inhibited HeLa cell invasion of metacyclic forms of isolates 569 and 588 by 90 and 70%, respectively.
A cell invasion assay performed in the presence of gastric mucin, mimicking the in vivo infection, showed an
inhibition of 70 to 75% in the internalization of gp82-deficient isolates but not of the CL isolate. The
recombinant gp82 exhibited an adhesive capacity toward gastric mucin much higher than that of gp30. Taken
together, our findings indicate that target cell entry of metacyclic trypomastigotes can be mediated either by
gp82 or gp30 but that efficient mucosal infection depends on the expression of gp82.
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CORTEZ, Mauro; NEIRA, Ivan; FERREIRA, Daniele; LUQUETTI, Alejandro O.; RASSI, Anis; ATAYDE, Vanessa D.; YOSHIDA, Nobuko. Infection by Trypanosoma cruzi metacyclic forms deficient in gp82 but expressing a related surface molecule, gp30. Infection and Immunity, Washington, v. 71, n. 11, p. 6184-6191, Nov. 2003.