24 research outputs found
Relevance of the Diversity among Members of the Trypanosoma Cruzi Trans-Sialidase Family Analyzed with Camelids Single-Domain Antibodies
The sialic acid present in the protective surface mucin coat of
Trypanosoma cruzi is added by a membrane anchored
trans-sialidase (TcTS), a modified sialidase that is expressed from a large gene
family. In this work, we analyzed single domain camelid antibodies produced
against trans-sialidase. Llamas were immunized with a recombinant
trans-sialidase and inhibitory single-domain antibody fragments were obtained by
phage display selection, taking advantage of a screening strategy using an
inhibition test instead of the classic binding assay. Four single domain
antibodies displaying strong trans-sialidase inhibition activity against the
recombinant enzyme were identified. They share the same
complementarity-determining region 3 length (17 residues) and have very similar
sequences. This result indicates that they likely derived from a unique clone.
Probably there is only one structural solution for tight binding inhibitory
antibodies against the TcTS used for immunization. To our surprise, this single
domain antibody that inhibits the recombinant TcTS, failed to inhibit the
enzymatic activity present in parasite extracts. Analysis of individual
recombinant trans-sialidases showed that enzymes expressed from different genes
were inhibited to different extents (from 8 to 98%) by the llama
antibodies. Amino acid changes at key positions are likely to be responsible for
the differences in inhibition found among the recombinant enzymes. These results
suggest that the presence of a large and diverse trans-sialidase family might be
required to prevent the inhibitory response against this essential enzyme and
might thus constitute a novel strategy of T. cruzi to evade the
host immune system
Galectin-1 Is Part of Human Trophoblast Invasion Machinery - A Functional Study In Vitro
Interactions of glycoconjugates with endogenous galectins, have been long proposed to participate in several reproductive processes including implantation. In human placenta gal-1, gal-3, gal-8, and gal-13 proteins are known to be present. Each of them has been proposed to play multiple functions, but so far no clear picture has emerged. We hypothesized that gal-1 participates in trophoblast invasion, and conducted Matrigel invasion assay using isolated cytotrophoblast from first trimester placenta and HTR-8/SVneo cell line to test it.<0.001) by Ox-gal-1 at 1 µg/ml. Both sets of results confirmed involvement of gal-1 in trophoblast invasion. Galectin profile of isolated cytotrophoblast and HTR-8/SVneo cells was established using RT-PCR and real-time PCR and found to consist of gal-1, gal-3 and gal-8 for both cell types. Only gal-1 was located at the trophoblast cell membrane, as determined by FACS analysis, which is consistent with the results of the functional tests.These findings qualify gal-1 as a member of human trophoblast cell invasion machinery
Metabolic labeling of surface neo-sialylglyconjugates catalyzed by trypanosoma cruzi trans-sialidase
Trypanosoma cruzi, the protozoan agent of Chagas disease, has evolved an innovative metabolic pathway by which protective sialic acid (SA) residues are scavenged from host sialylglycoconjugates and transferred onto parasite surface mucin-like molecules (or surface glycoconjugates from host target cells) by means of a unique trans-sialidase (TS) enzyme. TS-induced changes in the glycoprotein sialylation profile of both parasite and host cells are crucial for the establishment of a persistent T. cruzi infection and for the development of Chagas disease-associated pathogenesis. In this chapter, we describe a novel metabolic labeling method developed in our labs that enables straightforward identification and molecular characterization of SA acceptors of the TS-catalyzed reaction.Fil: Carlevaro, Giannina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Lantos, Andrés Bernardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina. Laboratorio Dr. Lantos; ArgentinaFil: Canepa, Gaspar Exequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina. Laboratory of Malaria and Vector Research National Institute of Allergy and Infectious Diseases, National Institutes of Health; Estados UnidosFil: Camara, Maria de Los Milagros. Universidad Argentina de la Empresa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Somoza, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Buscaglia, Carlos Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Campetella, Oscar Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Mucci, Juan Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentin
Galectin-8 Ameliorates Murine Autoimmune Ocular Pathology and Promotes a Regulatory T Cell Response
Galectins have emerged as potent immunoregulatory agents that control chronic inflammation through distinct mechanisms. Here, we report that treatment with Galectin-8 (Gal-8), a tandem-repeat member of the galectin family, reduces retinal pathology and prevents photoreceptor cell damage in a murine model of experimental autoimmune uveitis. Gal-8 treatment increased the number of regulatory T cells (Treg) in both the draining lymph node (dLN) and the inflamed retina. Moreover, a greater percentage of Treg cells in the dLN and retina of Gal-8 treated animals expressed the inhibitory coreceptor cytotoxic T lymphocyte antigen (CTLA)-4, the immunosuppressive cytokine IL-10, and the tissue-homing integrin CD103. Treg cells in the retina of Gal-8-treated mice were primarily inducible Treg cells that lack the expression of neuropilin-1. In addition, Gal-8 treatment blunted production of inflammatory cytokines by retinal T helper type (TH) 1 and TH17 cells. The effect of Gal-8 on T cell differentiation and/or function was specific for tissues undergoing an active immune response, as Gal-8 treatment had no effect on T cell populations in the spleen. Given the need for rational therapies for managing human uveitis, Gal-8 emerges as an attractive therapeutic candidate not only for treating retinal autoimmune diseases, but also for other TH1- and TH17-mediated inflammatory disorders