Publications by authors named "Sandriana R Silva"

6 Publications

  • Page 1 of 1

Detection of rabies virus antigen by the indirect rapid immunohistochemistry test in equines and comparisons with other diagnostic techniques.

Zoonoses Public Health 2020 09 14;67(6):651-657. Epub 2020 Jun 14.

Instituto Pasteur, São Paulo, Brazil.

Laboratory diagnosis of rabies in equines is essential for distinguishing the disease from other sources of encephalitis. Diagnosis by conventional techniques such as a direct fluorescent antibody test (dFAT) or viral isolation in mice or cell culture can be difficult, and the application of molecular biological methods may be necessary. We performed an indirect rapid immunohistochemistry test (iRIT) for the detection of the rabies virus (RABV) antigen in the central nervous system (CNS) of equines and compared the results with those of other diagnostic techniques. We reviewed result records from the Rabies Diagnosis Laboratory at Instituto Pasteur, São Paulo, Brazil, of 174 samples of equine CNS from July 2014 to June 2016, which were investigated by dFAT, rabies tissue culture infection test (RTCIT), mouse inoculation test (MIT) and reverse transcription-polymerase chain reaction (RT-PCR) followed by genetic sequencing. These samples, 29 presented divergent results among techniques and were selected for the performed in the iRIT. The detected positivity rate was 4/29 (14%) by dFAT, 5/28 (18%) by RTCIT, 10/29 (35%) by MIT and 26/27 (96%) by RT-PCR. We analysed 29 samples through imprints of the cortex, hippocampus, cerebellum and brainstem in slides fixed in 10% buffered formaldehyde. Eighteen samples were identified as positive (62%) by iRIT assay, representing a greater number of positive cases than that detected by dFAT, MIT and RTCIT but not by RT-PCR. Among the brain regions, the brainstem presented the highest positivity (78%), followed by the hippocampus (69%), cerebellum (67%) and cortex (67%). Our results provide evidence that iRIT can contribute to a rapid diagnosis of rabies in equines and that complementary tests should be used to improve diagnostic accuracy in this species.
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http://dx.doi.org/10.1111/zph.12745DOI Listing
September 2020

Isolation and Characterization of IgM and IgY Antibodies from Plasma of Magellanic Penguins (Spheniscus magellanicus).

Avian Dis 2015 Mar;59(1):79-86

Infectious diseases such as aspergillosis, avian malaria, and viral infections are significant threats to the conservation of penguins, leading to morbidity and mortality of these birds both in captivity and in the wild. The immune response to such infectious diseases is dependent on different mechanisms mediated by cells and soluble components such as antibodies. Antibodies or immunoglobulins are glycoproteins that have many structural and functional features that mediate distinct effector immune functions. Three distinct classes of antibodies have been identified in birds: immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin Y (IgY). In this study we aim to establish an efficient laboratory method to obtain IgM and IgY antibodies from plasma samples of healthy adult Magellanic penguins (Spheniscus magellanicus). The protocol was developed combining plasma delipidation, sequential precipitation with caprylic acid and ammonium sulfate, and size-exclusion chromatography. The efficiency of the protocol and the identity of the purified IgM and IgY antibodies were confirmed through enzyme-linked immunosorbent assay, Western blotting, one-dimensional and two-dimensional polyacrylamide gel electrophoresis, and lectin binding assay. Structural and physicochemical properties of IgM and IgY from Magellanic penguins were consistent with those of other avian species. This purification protocol will allow for more detailed studies on the humoral immunity of penguins and for the development of high specificity serologic assays to test Magellanic penguins for infectious pathogens.
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http://dx.doi.org/10.1637/10738-112913-regDOI Listing
March 2015

TLR2- and 4-independent immunomodulatory effect of high molecular weight components from Ascaris suum.

Mol Immunol 2014 Mar 19;58(1):17-26. Epub 2013 Nov 19.

Laboratory of Immunopathology, Butantan Institute, São Paulo, SP, Brazil. Electronic address:

Components of high molecular-weight (PI) obtained from Ascaris suum extract down-regulate the Th1/Th2-related immune responses induced by ovalbumin (OVA)-immunization in mice. Furthermore, the PI down-modulates the ability of dendritic cells (DCs) to activate T lymphocytes by an IL-10-mediated mechanism. Here, we evaluated the role of toll like receptors 2 and 4 (TLR2 and 4) in the modulatory effect of PI on OVA-specific immune response and the PI interference on DC full activation. An inhibition of OVA-specific cellular and humoral responses were observed in wild type (WT) or in deficient in TLR2 (TLR2(-/-)) or 4 (TLR4(-/-)) mice immunized with OVA plus PI when compared with OVA-immunized mice. Low expression of class II MHC, CD40, CD80 and CD86 molecules was observed in lymph node (LN) cells from WT, TLR2(-/-) or TLR4(-/-) mice immunized with OVA plus PI compared with OVA-primed cells. We also verified that PI was able to modulate the activation of DCs derived from bone marrow of WT, TLR2(-/-) or TLR4(-/-) mice induced in vitro by agonists of TLRs, as observed by a decreased expression of class II MHC and costimulatory molecules and by low secretion of pro-inflammatory cytokines. Its effect was accompanied by IL-10 synthesis. In this sense, the modulatory effect of PI on specific-immune response and DC activation is independent of TLR2 or TLR4.
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http://dx.doi.org/10.1016/j.molimm.2013.10.011DOI Listing
March 2014

Stable assemblies of cationic bilayer fragments and CpG oligonucleotide with enhanced immunoadjuvant activity in vivo.

J Control Release 2012 Jun 21;160(2):367-73. Epub 2011 Oct 21.

Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970, São Paulo, SP, Brazil.

The cationic lipid dioctadecyldimethylammonium bromide (DODAB) and the CpG oligonucleotide (CpG) have been separately used as potent immunoadjuvants driving Th1 responses. Here DODAB bilayer fragments (BF) and CpG (5'-TTGACGTTCG-3') assemblies have their physical properties and immunoadjuvant activity determined using ovalbumin (OVA) as a model antigen. At 0.1 mg/mL OVA, the dependence of DODAB BF/OVA size and zeta-potential on time and [DODAB] establishes 0.1 mM DODAB as suitable for obtaining stable and cationic DODAB BF/OVA assemblies. At 0.1 mM DODAB, 0.1 mg/mL OVA and 0.006 mM CpG, the zeta-potential is zero. At [CpG]>0.006 mM, good colloidal stability for the anionic assemblies is due to charge overcompensation. At 0.020 mM CpG, these DODAB BF/OVA/CpG assemblies are highly effective in vivo generating responses similar to those elicited by the stable and cationic DODAB BF/OVA. The anti-OVA DTH reaction and the secretion of IFN-gamma and IL-12 are 6, 42 and 9 times larger for the DODAB BF/OVA/CpG-immunized mice than the same responses by OVA-immunized mice, respectively. This work shows for the first time that charge of small assemblies is not important to determine the immune response.
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http://dx.doi.org/10.1016/j.jconrel.2011.10.017DOI Listing
June 2012

Sialic acid residues are essential for the anaphylactic activity of murine IgG1 antibodies.

J Immunol 2008 Dec;181(12):8308-14

Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.

Glycosylation of the Ab molecule is essential for maintaining the functional structure of Fc region and consequently for Ab-mediated effector functions, such as binding to cells or complement system activation. Alterations in the composition of the sugar moiety can dramatically influence Ab activity; however, it is not completely clear how differences in the N-linked oligosaccharide structure impact the biological function of Abs. We have described that murine IgG1 Abs can be separated according to their ability to elicit in vivo anaphylaxis in a fraction of anaphylactic and other of non-anaphylactic molecules. Furthermore, we showed that the N-linked oligosaccharide chain is essential for the structural conformation of the anaphylactic IgG1, the binding to FcgammaRIII on mast cells, and, consequently, for the ability to mediate anaphylactic reactions. In this study, we evaluated the contribution of individual sugar residues to this biological function. Differences in the glycan composition were observed when we analyzed oligosaccharide chains from anaphylactic or non-anaphylactic IgG1, mainly the presence of more sialic acid and fucose residues in anaphylactic molecules. Interestingly, the enzymatic removal of terminal sialic acid residues in anaphylactic IgG1 resulted in loss of the ability to trigger mast cell degranulation and in vivo anaphylactic reaction, similarly to the deglycosylated IgG1 Ab. In contrast, fucose removal did not affect the anaphylactic function. Therefore, we demonstrated that the ability of murine IgG1 Abs to mediate anaphylaxis is directly dependent on the amount of sialic acid residues associated to the oligosaccharide chain attached to the Fc region of these molecules.
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http://dx.doi.org/10.4049/jimmunol.181.12.8308DOI Listing
December 2008

Immunosuppressive components of Ascaris suum down-regulate expression of costimulatory molecules and function of antigen-presenting cells via an IL-10-mediated mechanism.

Eur J Immunol 2006 Dec;36(12):3227-37

Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.

High-molecular-weight components (PI) of Ascaris suum suppress both cell-mediated and humoral responses against ovalbumin (OVA) via an IL-4/IL-10-dependent mechanism. The aim of this work was to investigate the effect of PI on the ability of APC to activate T cells and the role of IL-10 in this process. Flow cytometry analyses of MHC class II, CD80, CD86 and CD40 molecules on LN cells from mice immunized with OVA or OVA+PI showed that PI inhibits expression of these molecules on unfractionated cells and on purified CD11c(+) cells. A low proliferative response was obtained when OVA-specific TCR-Tg T cells were incubated with CD11c(+) cells from OVA+PI-immunized mice pulsed with OVA, when compared to those incubated with cells from OVA-immunized mice. Similar results were obtained using as APC CD11c(+) cells from OVA-immunized mice pulsed with OVA+PI, which also expressed less of the four markers. The inhibitory effect of PI on both the expression of costimulatory molecules and the induction of T cell proliferation was abolished in IL-10-deficient mice. Our data indicate that the potent immunosuppressive effect of A. suum extract components on the host immune system is primarily related to their property of down-regulating the Ag-presenting ability of DC via an IL-10-mediated mechanism.
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http://dx.doi.org/10.1002/eji.200636110DOI Listing
December 2006