title: Trypanosoma cruzi infection modulates intrathymic contents of extracellular matrix ligands and receptors and alters thymocyte migration.
abstract: Several T cell abnormalities have been described in the course of acute Trypanosoma cruzi infection in mice, including severe effects on the thymus. In the present study, looking at the expression of extracellular matrix ligands in the thymus, we observed that deposits of fibronectin and laminin increased progressively during the course of infection, reaching a maximum at the peak of parasitemia and thymic atrophy. Concomitantly, membrane expression of fibronectin and laminin receptors (VLA-4, VLA-5 and VLA-6) was also enhanced on thymocyte subsets of infected mice. These results correlated with changes in intrathymic thymocyte migration ability during the acute phase of infection, when a higher fibronectin-dependent transmigratory activity of CD4(+)CD8(+) thymocytes was observed. Strikingly, we detected higher frequency of immature and high VLA-expressing CD4(+)CD8(+) T cells in the peripheral lymphoid organs of infected mice at the peak of parasitemia. These cells seemed to be thymus dependent, since significantly lower amounts of them were found in thymectomized mice, and some of them carry "prohibited" Vbeta segments of the TCR. Our data suggest an imbalance in the intrathymic cell trafficking following acute T. cruzi infection, likely due to dysregulated extracellular matrix-dependent interactions.
authors.affiliation: Laboratory of Cell Biology, Department of Ultrastructure and Cell Biology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Vinícius
authors.initials: V
authors.lastname: Cotta-de-Almeida
authors.forename: Adriana
authors.initials: A
authors.lastname: Bonomo
authors.forename: Daniella Arêas
authors.initials: DA
authors.lastname: Mendes-da-Cruz
authors.forename: Ingo
authors.initials: I
authors.lastname: Riederer
authors.forename: Juliana
authors.initials: J
authors.lastname: De Meis
authors.forename: Kátia Regina Ferreira
authors.initials: KR
authors.lastname: Lima-Quaresma
authors.forename: Adriana
authors.initials: A
authors.lastname: Vieira-de-Abreu
authors.forename: Déa Maria Serra
authors.initials: DM
authors.lastname: Villa-Verde
authors.forename: Wilson
authors.initials: W
authors.lastname: Savino
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D014355:Chagas Disease / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D051379:Mice; D016024:Receptors, Cytoadhesin / Q000096:biosynthesis / Q000235:genetics; D013950:Thymus Gland / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000472:pathogenicity*
chemical_list: D016024:Receptors, Cytoadhesin