Serological detection of antibodies against Paracoccidioides brasiliensis in dogs with leishmaniasis.
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ABSTRACT:
SUBMITTER: Silveira LH
PROVIDER: S-EPMC2780595 | biostudies-other | 2006 Nov
REPOSITORIES: biostudies-other
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Project description:Nearly 800 nucleotides from the 5' terminus of the 28S ribosomal gene of Paracoccidioides brasiliensis were sequenced, and a 14-base DNA probe specific for this species was identified. Hybridization results showed that the probe identified P. brasiliensis ribosomal DNA in a panel of ribosomal DNAs representing a total of 48 species of fungi.
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Project description:Paracoccidioidomycosis (PCM) is a systemic granulomatous mycosis whose agent is Paracoccidioides brasiliensis. In the culture supernatant, the fungus expresses glycoproteins of from 13 to 148 kDa. A cell surface glycoprotein of 43 kDa is the major antigenic component of P. brasiliensis. Another expressed glycoprotein, gp70, is recognized by 96% of sera from PCM patients and is able to induce lymphoproliferation. Since, little is known about this glycoprotein, we produced monoclonal antibodies (MAbs) against gp70 to isolate the molecule from total fungus extracts and to investigate its possible role in the pathogenesis of PCM. Using these MAbs, it was observed by confocal microscopy that gp70 is located mainly in the intracellular compartment of the fungus, although it was also detected in the culture supernatant. Based on observations showing that gp43 has a down-regulatory effect on mouse peritoneal macrophages, we tested the effects of gp70 on their phagocytic ability. Purified gp70 was able to inhibit the activity of macrophages through the mannose receptors and also through the Fc receptors; the latter effect was not observed with gp43. gp70 inhibits NO and H(2)O(2) liberation by peritoneal macrophages in vitro, as does gp43. Results obtained with gp43 led us to hypothesize that gp70 could act as an escape mechanism for fungal establishment in primary infections. To corroborate this hypothesis, we analyzed the effect of passive immunization of mice during infection with P. brasiliensis using anti-gp70 MAbs. This treatment almost completely abolished granuloma formation in the lungs, suggesting that the protein facilitates fungal establishment and progression of lesions in primary infection.
| S-EPMC219562 | biostudies-other
Project description:Coronavirus disease of 2019 (COVID-19) caused by severe acute respiratory syndrome virus type 2 (SARS-CoV-2) is an emerging severe acute respiratory disease affecting global human health. In this study, a large-scale serological survey of antibodies against SARS-CoV-2 in dogs and cats was conducted during the first and second waves of COVID-19 outbreaks in Thailand, from April to December 2020. A total of 3215 serum samples were collected from dogs (n = 2102) and cats (n = 1113) living in Bangkok and in the vicinities. Serum samples were tested for SARS-CoV-2 antibodies by using an indirect multispecies enzyme-linked immunosorbent assay (ELISA). Positive and suspected samples were additionally tested for neutralizing antibodies by the surrogate virus neutralization test (sVNT). The indirect ELISA results showed that 1.66% (35 out of 2103) of dogs and 0.36% (four out of 1112) of cats were positive for SARS-CoV-2 antibodies. The sVNT results showed that all ELISA-positive and suspected samples were negative for neutralizing antibodies. Positive serum samples (35 dogs and four cats) were obtained from clinically healthy animals and animals with mild respiratory signs aged <1-13 years living in Bangkok and Samutprakarn Provinces. In summary, a serological survey revealed evidence of anti-N-IgG antibodies suggesting SARS-CoV-2 exposure in both dogs and cats during the first and second COVID-19 outbreaks in Thailand.
| S-EPMC8447141 | biostudies-literature
Project description:Toll-like receptors (TLRs) comprise the best-characterized pattern-recognition receptor (PRR) family able to activate distinct immune responses depending on the receptor/adaptor set assembled. TLRs, such as TLR2, TLR4 and TLR9, and their signaling were shown to be important in Paracoccidioides brasiliensis infections. However, the role of the endosomal TLR3 in experimental paracoccidioidomycosys remains obscure. In vitro assays, macrophages of the bone marrow of WT or TLR3-/- mice were differentiated for evaluation of their microbicidal activity. In vivo assays, WT or TLR3-/- mice were infected intratracheally with Paracoccidioides brasiliensis yeasts for investigation of the lung response type induced. The cytotoxic activity of CD8+ T cells was assessed by cytotoxicity assay. To confirm the importance of CD8+ T cells in the control of infection in the absence of tlr3, a depletion assay of these cells was performed. Here, we show for the first time that TLR3 modulate the infection against Paracoccidioides brasiliensis by dampening pro-inflammatory response, NO production, IFN+CD8+T, and IL-17+CD8+T cell activation and cytotoxic function, associated with granzyme B and perforin down regulation. As conclusion, we suggest that TLR3 could be used as an escape mechanism of the fungus in an experimental paracoccidioidomycosis.
| S-EPMC6335947 | biostudies-literature
Project description:Genotyping of the genus Paracoccidioides showed its diversity and geographical distribution. Four species constituting the Paracoccidioides brasiliensis complex and Paracoccidioides lutzii are etiological agents of paracoccidioidomycosis (PCM). However, there are no studies comparing the clinical and epidemiological aspects between PCM caused by the P. brasiliensis complex and by P. lutzii. Demographic and clinical data from 81 patients with PCM-confirmed by mycological and/or histopathological examination-from Mato Grosso do Sul state (Brazil) were studied. All patients underwent serology by immunodiffusion with antigens obtained from the P. brasiliensis complex (ExoPb and gp43) and Cell Free Antigens obtained from P.lutzii (CFAPl).The cases were classified regarding their serological profile into three groups: G1: PCM patients seropositive to ExoPb and/or gp43 and seronegative to CFAPl (n = 51), assumed to have PCM caused by P. brasiliensis complex; G2: PCM patients seronegative to gp43 and seropositive to CFAPl (n = 16), with PCM caused by P. lutzii; and G3: PCM patients seropositive to ExoPb or gp43 and seropositive to CFAPl (n = 14), with undetermined serological profile, was excluded from the analyses. The Fisher's exact test or the Mann-Whitney U test, and cluster analysis according to Ward's method and Euclidean distance were used to analyze the results. Patients with serological profile suggestive of P. lutzii lived predominantly in municipalities in the Central and Southern regions of the state, while those with serological profile indicative of the P. brasiliensis complex were distributed throughout the state. No differences were found between the two groups regarding gender, age, schooling, rural work, clinical form, severity, organs involved, intensity of pulmonary involvement, degree of anemia, erythrocyte sedimentation rate values, and therapeutic response. PCM patients with serological profile suggestive of P. lutzii and PCM patients with serological profile indicative of P. brasiliensis complex showed the same clinical and radiological presentations.
| S-EPMC7447013 | biostudies-literature
Project description:A nested PCR assay for the detection of Paracoccidioides brasiliensis DNA was evaluated, using a sequence of the immunogenic gp43 gene as a target. This gene encodes an outer membrane protein unique to this dimorphic fungus. DNA from six clinical isolates and the ATCC strain 60885 of P. brasiliensis, as well as DNA from closely related fungi, was examined to determine detection limits and cross-reactions. PCR was done on DNA extracts of lung homogenates from 23 experimentally P. brasiliensis-infected and two uninfected BALB/c mice and from 20 Histoplasma capsulatum-infected ICR mice. The results were compared to quantitative cultures. A detection limit of 0.5 fg of specific DNA was determined using cloned plasmid DNA. In all seven P. brasiliensis isolates, the expected 196-bp nested PCR product was found. Their sequences were 100% identical to the gp43 gene sequence in GenBank. DNA extracts of all other, related fungi were negative. The PCR assay was positive in 21 out of 23 culture-positive lung homogenates with concentrations of 1 x 10(3) to 1.3 x 10(7) CFU of P. brasiliensis per g of lung. Uninfected BALB/c mice and H. capsulatum-infected mice samples gave negative results. The high sensitivity and specificity of this new nested PCR assay for the detection of P. brasiliensis in tissue samples were demonstrated. The assay may be useful for diagnosis in human tissue samples.
| S-EPMC87153 | biostudies-literature
Project description:The granulomatous lesion resulting from infection with the fungus Paracoccidioides brasiliensis is characterized by a compact aggregate of mature cells, surrounded by a fibroblast- and collagen-rich content. Granuloma formation requires signaling elicited by inflammatory molecules such as members of the interleukin-1 family. Two members of this family have been thoroughly studied, namely IL-1? and IL-1?. In this study, we addressed the mechanisms underlying IL-1? secretion and its functional role on the host resistance to fungal infection. We found that, the expression of caspase-11 triggered by P. brasiliensis infection of macrophages depends on IFN-? production, because its inhibition reduced procaspase-11 levels. Curiously, caspase-11 deficiency did not impair IL-1? production, however caspase-11 was required for a rapid pore-mediated cell lysis. The plasma membrane rupture facilitated the release of IL-1?, which was necessary to induce NO production and restrict fungal replication. Furthermore, P. brasiliensis-infected macrophages required IL-1? to produce optimal levels of IL-6, a major component of Th17 lymphocyte differentiation. Indeed, IL-1? deficiency accounted for a significant reduction of Th17 lymphocytes in lungs of infected mice, correlating with diminished neutrophil infiltration in the lungs. Strikingly, we identified that IL-1? directly reprograms the transcriptional profile of Th17-committed lymphocytes, increasing cellular proliferation, as for boosting IL-17 production by these cells. Beyond neutrophil chemotaxis in vivo, IL-17 also amplified IL-1? production by infected macrophages in vitro, endorsing a critical amplification loop of the inflammatory response. Therefore, our data suggest that the IFN-?/caspase-11/IL-1? pathway shapes a protective antifungal Th17 immunity, revealing a molecular mechanism underlying the cross-talk between innate and adaptive immunity.
| S-EPMC6715237 | biostudies-literature
Project description:Paracoccidioidomycosis (PCM) is a granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. The immunoglobulin classes and isotypes of antibodies directed to acidic glycosphingolipids (GSLs) and glucosylceramide of P. brasiliensis were determined by enzyme-linked immunosorbent assay of sera from 31 PCM patients. The reactivities of 38 serum samples were analyzed by considering the stage of treatment: before antifungal treatment (n = 10), during 1 to 4 months of treatment (T1-4; n = 9), during 5 to 12 months of treatment (T5-12; n = 9), and posttreatment (PT; n = 10). Sera from healthy subjects (n = 12) were used as controls. Only the GSL Pb-1 antigen, which presents the carbohydrate structure Galfbeta1-6(Manalpha1-3)Manbeta1, was reactive with the PCM patient sera. The PCM patient sera did not react with Pb-2, which lacks the Galf residue and which is considered the biosynthetic precursor of Pb-1, indicating that the Galf residue is essential for antibody reactivity. The Pb-1 glycolipid from nontreated patients elicited a primary immune response with immunoglobulin M (IgM) production and subsequent switching to IgG1 production. The IgG1 titer increased after the start of antifungal treatment (T1-4 group), and general decreases in the anti-Pb-1 antibody titers were observed after 5 months of treatment (T5-12 and PT groups). The Pb-1 antigen, an acidic GSL with terminal Galf residue, has potential application as an elicitor of the host immune response in patients with PCM.
| S-EPMC1797792 | biostudies-literature
Project description:Gene expression modulation by paraquat-induced oxidative stress conditions in P. brasiliensis
| PRJNA176420 | ENA
Project description:Transcriptome analysis of Paracoccidioides brasiliensis cells undergoing the Mycelium-to-Yeast transition
| PRJNA92775 | ENA