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More than 70% of bacteria are resistant to all or nearly all known antimicrobials, creating the need for the development of new types of antimicrobials or the use of "last-line" antimicrobial therapies for the treatment of multi-resistant bacteria. These antibiotics include Glycopeptide (Vancomycin), Polymyxin (Colistin), Lipopeptide (Daptomycin), and Carbapenem (Meropenem). However, due to the toxicity of these types of molecules, it is necessary to develop new rapid methodologies to be used in Therapeutic Drug Monitoring (TDM). TDM could improve patient outcomes and reduce healthcare costs by enabling a favorable clinical outcome. In this way, personalized antibiotic therapy emerges as a viable option, offering optimal dosing for each patient according to pharmacokinetic (PK) and pharmacodynamic (PD) parameters. Various techniques are used for this monitoring, including high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and immunoassays. The objective of this study is the development and characterization by ELISA of specific polyclonal antibodies for the recognition of the antibiotics Vancomycin (glycopeptide), Colistin (polymyxin), Daptomycin (lipopeptide), and Meropenem (carbapenem) for future applications in the monitoring of these antibiotics in different fluids, such as human plasma. The developed antibodies are capable of recognizing the antibiotic molecules with good detectability, showing an IC50 of 0.05 nM for Vancomycin, 7.56 nM for Colistin, 183.6 nM for Meropenem, and 13.82 nM for Daptomycin. These antibodies offer a promising tool for the precise and effective therapeutic monitoring of these critical antibiotics, potentially enhancing treatment efficacy and patient safety.
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This chapter describes a step-by-step protocol for rapid serological quantification of global DNA methylation by enzyme-linked immunosorbent assay (ELISA) in plant tissue culture specimens. As a case study model, we used the coconut palm (Cocos nucifera), from which plumules were subjected to somatic embryogenesis followed by embryogenic calli multiplication. DNA methylation is one of the most common epigenetic markers in the regulation of gene expression. DNA methylation is generally associated with non-expressed genes, that is, gene silencing under certain conditions, and the degree of DNA methylation can be used as a marker of various physiological processes, both in plants and in animal cells. Methylation consists of adding a methyl radical to carbon 5 of the DNA cytosine base. Herein, the global DNA methylation was quantified by ELISA with antibodies against methylated cytosines using a commercial kit (Zymo-Research™). The method allowed the detection of methylation in total DNA extracts from coconut palm embryogenic calli (arising from somatic embryogenesis) cultivated in liquid or solid media by using antibodies against methylated cytosines and enzymatic development with a colorimetric substrate. Control samples of commercially provided Escherichia coli bacterial DNA with previously known methylation percentages were included in the ELISA test to construct an experimental methylation standard curve. The logarithmic regression of this E. coli standard curve allowed methylation quantification in coconut palm samples. The present ELISA methodology, applied to coconut palm tissue culture specimens, is promising for use in other plant species and botanical families. This chapter is presented in a suitable format for use as a step-by-step laboratory procedure manual, with theoretical introduction information, which makes it easy to apply the protocol in samples of any biological nature to evaluate DNA global methylation associated with any physiological process.
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Metilação de DNA , Ensaio de Imunoadsorção Enzimática , Epigênese Genética , Ensaio de Imunoadsorção Enzimática/métodos , DNA de Plantas/genética , Cocos/genética , Técnicas de Cultura de Tecidos/métodos , Técnicas de Embriogênese Somática de Plantas/métodosRESUMO
Introduction. Avian reovirus (ARV) is associated with arthritis/tenosynovitis and malabsorption syndrome in chickens. The σC and σB proteins, both exposed to the virus capsid, are highly immunogenic and could form the basis for diagnostic devices designed to assess the immunological status of the flock.Gap Statement. Commercial ARV ELISAs cannot distinguish between vaccinated and infected animals and might not detect circulating ARV strains.Aim. We aimed to develop a customized test to detect the circulating field ARV strains as well as distinguish between vaccinated and unvaccinated animals.Methodology. We developed ELISA assays based on recombinant (r) σB, σC and the nonstructural protein σNS and tested them using antisera of vaccinated and unvaccinated chickens as well as negative controls. Fragments of σB and σC proteins were also used to study regions that could be further exploited in diagnostic tests.Results. Vaccinated and unvaccinated birds were positive by commercial ELISA, with no difference in optical density values. In contrast, samples of unvaccinated animals showed lower absorbance in the rσB and rσC ELISA tests and higher absorbance in the rσNS ELISA test than the vaccinated animals. Negative control samples were negative in all tests. Fragmentation of σB and σC proteins showed that some regions can differentiate between vaccinated and unvaccinated animals. For example, σB amino acids 128-179 (σB-F4) and σC amino acids 121-165 (σC-F4) exhibited 85 and 95% positivity among samples of vaccinated animals but only 5% and zero positivity among samples of unvaccinated animals, respectively.Conclusion. These data suggest that unvaccinated birds might have been exposed to field strains of ARV. The reduction in absorbance in the recombinant tests possibly reflects an increased specificity of our test since unvaccinated samples showed less cross-reactivity with the vaccine proteins immobilized on ELISAs. The discrepant results obtained with the protein fragment tests between vaccinated and unvaccinated animals are discussed in light of the diversity between ARV strains.
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Galinhas , Ensaio de Imunoadsorção Enzimática , Orthoreovirus Aviário , Doenças das Aves Domésticas , Proteínas Recombinantes , Infecções por Reoviridae , Animais , Orthoreovirus Aviário/imunologia , Orthoreovirus Aviário/genética , Orthoreovirus Aviário/isolamento & purificação , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/veterinária , Infecções por Reoviridae/veterinária , Infecções por Reoviridae/diagnóstico , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/diagnóstico , Proteínas Recombinantes/imunologia , Anticorpos Antivirais/sangue , Proteínas do Capsídeo/imunologia , Proteínas do Capsídeo/genética , Proteínas Virais/imunologia , Proteínas Virais/genéticaRESUMO
We conducted a development and standardization of an IgG ELISA assay for serological detection of human orthohantavirus infections using the recombinant antigen rLECH13 produced in bacterial and derived from the LECHV. The evaluation and standardization were carried out by analyzing serum samples from a total of 50 patients with confirmed Hantavirus Pulmonary Syndrome (HPS) diagnosis through the reference technique, 50 negative sera, and 53 patients with other medical conditions. The data from the assay analysis showed a diagnostic sensitivity value of 95% and a diagnostic specificity of 80%. The high sensitivity of this novel assay leads us to conclude that rLECH13 is a feasible option for use in the immunodiagnostic of orthohantavirus infection. Additionally, it is crucial to have an antigen that can be produced under conditions that do not require highly complex laboratories. Furthermore, the new assay is cost-effective, reproducible, and demonstrates excellent performance.
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Anticorpos Antivirais , Ensaio de Imunoadsorção Enzimática , Infecções por Hantavirus , Orthohantavírus , Sensibilidade e Especificidade , Humanos , Ensaio de Imunoadsorção Enzimática/métodos , Orthohantavírus/imunologia , Orthohantavírus/genética , Orthohantavírus/isolamento & purificação , Argentina , Infecções por Hantavirus/diagnóstico , Anticorpos Antivirais/sangue , Proteínas do Nucleocapsídeo/imunologia , Proteínas do Nucleocapsídeo/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Imunoglobulina G/sangue , Antígenos ViraisRESUMO
Streptococcosis caused by Streptococcus agalactiae (S. agalactiae) is a major bacterial disease affecting the production of Nile tilapia (Oreochromis niloticus L.), causing significant economic losses due to mortality in the growing phase. Vaccination is the most effective method for preventing streptococcosis on Nile tilapia farms. In Brazil, the major tilapia-producing regions have long production cycles (6-10 months) and harvest tilapias weighing over 900 g for fillet production. Thus, data on the duration of the humoral immune response and protection in farmed tilapia have not been reported or are poorly described. Furthermore, the efficiency of serological testing for the long-term monitoring of immune responses induced by vaccination against S. agalactiae has never been addressed. This study evaluated the duration of protection and humoral immune response induced in Nile tilapia vaccinated against S. agalactiae until 300 days post-vaccination (dpv). The immunization trial was composed of two groups: vaccinated (Vac), vaccinated intraperitoneally with a commercial vaccine, and unvaccinated (NonVac) group, injected fish with sterile saline solution. At 15, 30, 150, 180, 210, and 300 dpv, blood sampling was conducted to detect anti-S. agalactiae IgM antibodies using indirect Enzyme-Linked Immunosorbent Assay (ELISA), and the fish were challenged with pathogenic S. agalactiae to determine the duration of vaccine protection through relative percentage survival (RPS). Spearman's rank correlation was performed between the ELISA optical density (OD) of vaccinated tilapia and the duration of vaccine protection (RPS). The mean cumulative mortality in NonVac and Vac groups ranged from 65 to 90% and less than 35%, respectively. The average RPS was 71, 93, 94, 70, 86, and 67% at 15, 30, 150, 180, 210, and 300 dpv, respectively. RPS revealed that the vaccine provided protection from 15 to 300 dpv. The specific anti-S. agalactiae IgM antibody levels were significantly higher in the Vac group than that non-Vac group up to 180 dpv. The vaccinated fish exhibited significant protection for up to 10 months after vaccination. There was a positive correlation between the antibody response and RPS. This study revealed that a single dose of commercial vaccine administered to Nile tilapia can confer long-term protection against S. agalactiae and that indirect ELISA can monitor the duration of the humoral immune response for up to six months following vaccination. Finally, vaccine protection over six months can be associated with other components of the fish immune system beyond the humoral immune response by IgM antibodies.
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Leptospirosis is a globally distributed infectious disease caused by pathogenic spirochetes of the Leptospira genus, often overlooked. It is estimated that the disease affects approximately one million people annually, resulting in more than 58,900 deaths. The gold standard for serodiagnosis of leptospirosis is the Microscopic Agglutination Test (MAT). However, the limitations of this technique necessitate the exploration of alternative diagnostic methods. In this study, we evaluated the ErpY-like recombinant protein (rErpY-like) in the development of a serologic diagnostic assay for human leptospirosis. Eighty-six human sera samples, characterized by MAT, underwent evaluation through indirect IgM-ELISA and IgG-ELISA. The sensitivity and specificity values obtained from IgM-ELISA were 60% and 76%, respectively, while those from IgG-ELISA were 96.4% and 100%, respectively. The use of the rErpY-like protein in both IgM-ELISA and IgG-ELISA proves to be a sensitive and specific method for antibody detection. This could potentially serve as a valuable alternative tool in the diagnosis of human leptospirosis.
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Anticorpos Antibacterianos , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G , Imunoglobulina M , Leptospira , Leptospirose , Sensibilidade e Especificidade , Testes Sorológicos , Leptospirose/diagnóstico , Leptospirose/imunologia , Leptospirose/microbiologia , Leptospirose/sangue , Humanos , Anticorpos Antibacterianos/sangue , Imunoglobulina M/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Imunoglobulina G/sangue , Leptospira/imunologia , Testes Sorológicos/métodos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/genética , Antígenos de Bactérias/imunologiaRESUMO
Toxoplasma gondii is described as a potential cause of abortion in goats and as a threat to public health. To estimate the prevalence of goats infected by T. gondii, in different cities in the Espírito Santo State, and to identify possible risk factors for infection a serological study was conducted. A total of 146 goat serum samples from the cities of Cariacica, Serra and Vila Velha were analyzed. The presence of IgG Class Immunoglobulins was serologically evaluated by Immunofluorescence antibody test (IFAT) and by Enzyme-linked Immunosorbent Assay (ELISA). The seroprevalence of anti-T. gondii was 46.6% (68/146) in both techniques and the same samples got the same results in both techniques. Among the analyzed sera, 70.6% (48/68) exhibited high-avidity IgG antibodies, and 29.4% (20/68) exhibited low-avidity IgG antibodies, suggesting that the infection was chronic in the infected animals. Female sex, age group over two years old, water from the public supply system, storage of food and supplies in an open and unprotected place, and the presence of a domestic cat on the property were identified as risk factors for T. gondii infection in goats. The state of Espirito Santo has a high frequency of infected goats, and this is the first research on caprine toxoplasmosis seroepidemiology in that region.
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Anticorpos Antiprotozoários , Doenças das Cabras , Cabras , Imunoglobulina G , Toxoplasma , Toxoplasmose Animal , Animais , Cabras/parasitologia , Estudos Soroepidemiológicos , Brasil/epidemiologia , Toxoplasmose Animal/epidemiologia , Toxoplasmose Animal/parasitologia , Doenças das Cabras/epidemiologia , Doenças das Cabras/parasitologia , Fatores de Risco , Toxoplasma/imunologia , Feminino , Masculino , Anticorpos Antiprotozoários/sangue , Imunoglobulina G/sangue , Ensaio de Imunoadsorção Enzimática/veterinária , PrevalênciaRESUMO
SARS-CoV-2 vaccines have contributed to attenuating the burden of the COVID-19 pandemic by promoting the development of effective immune responses, thus reducing the spread and severity of the pandemic. A clinical trial with the Sputnik-V vaccine was conducted in Venezuela from December 2020 to July 2021. The aim of this study was to explore the antibody reactivity of vaccinated individuals towards different regions of the spike protein (S). Neutralizing antibody (NAb) activity was assessed using a commercial surrogate assay, detecting NAbs against the receptor-binding domain (RBD), and a plaque reduction neutralization test. NAb levels were correlated with the reactivity of the antibodies to the spike regions over time. The presence of Abs against nucleoprotein was also determined to rule out the effect of exposure to the virus during the clinical trial in the serological response. A high serological reactivity was observed to S and specifically to S1 and the RBD. S2, although recognized with lower intensity by vaccinated individuals, was the subunit exhibiting the highest cross-reactivity in prepandemic sera. This study is in agreement with the high efficacy reported for the Sputnik V vaccine and shows that this vaccine is able to induce an immunity lasting for at least 180 days. The dissection of the Ab reactivity to different regions of S allowed us to identify the relevance of epitopes outside the RBD that are able to induce NAbs. This research may contribute to the understanding of vaccine immunity against SARS-CoV-2, which could contribute to the design of future vaccine strategies.
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Lateral flow immunoassays (LFIA) for antibody detection represent cost-effective and user-friendly tools for serology assessment. This study evaluated a new LFIA prototype developed with a recombinant chimeric antigen from the spike/S and nucleocapsid/N proteins to detect anti-SARS-CoV-2 IgG antibodies. The evaluation of LFIA sensitivity and specificity used 811 serum samples from 349 hospitalized, SARS-CoV-2 RT-qPCR positive COVID-19 patients, collected at different time points and 193 serum samples from healthy controls. The agreement between ELISA results with the S/N chimeric antigen and LFIA results was calculated. The LFIA prototype for SARS-CoV-2 using the chimeric S/N protein demonstrated 85 % sensitivity on the first week post symptoms onset, reaching 94 % in samples collected at the fourth week of disease. The agreement between LFIA and ELISA with the same antigen was 92.7 %, 0.827 kappa Cohen value (95 % CI [0.765-0.889]). Further improvements are needed to standardize the prototype for whole blood use. The inclusion of the novel chimeric S + N antigen in the COVID-19 IgG antibody LFIA demonstrated optimal agreement with results from a comparable ELISA, highlighting the prototype's potential for accurate large-scale serologic assessments in the field in a rapid and user-friendly format.
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Diagnosing canine visceral leishmaniasis (CVL) in Brazil faces challenges due to the limitations regarding the sensitivity and specificity of the current diagnostic protocol. Therefore, it is urgent to map new antigens or enhance the existing ones for future diagnostic techniques. Immunoinformatic tools are promising in the identification of new potential epitopes or antigen candidates. In this study, we evaluated peptides selected by epitope prediction for CVL serodiagnosis in ELISA assays. Ten B-cell epitopes were immunogenic in silico, but two peptides (peptides No. 45 and No. 48) showed the best performance in vitro. The selected peptides, both individually and in combination, were highly diagnostically accurate, with sensitivities ranging from 86.4% to 100% and with a specificity of approximately 90%. We observed that the combination of peptides showed better performance when compared to peptide alone, by detecting all asymptomatic dogs, showing lower cross-reactivity in sera from dogs with other canine infections, and did not detect vaccinated animals. Moreover, our data indicate the potential use of immunoinformatic tools associated with ELISA assays for the selection and evaluation of potential new targets, such as peptides, applied to the diagnosis of CVL.