RESUMO
The diagnosis of tegumentary leishmaniasis (TL) is hampered by variable sensitivity and/or specificity of the tests. Serological assays are suitable to diagnose visceral leishmaniasis (VL); however, they present low performance for the detection of TL cases. Additionally, blood collection to obtain patient serum represents a challenge, as it is an invasive and uncomfortable procedure, requiring laboratorial infrastructure and trained professionals. In this context, the present study proposed to evaluate patient urine to detect TL, given that this analyte has proven to be effective in ELISA experiments for the detection of VL cases. For this, a Leishmania protein called LiHyV, two specific B-cell epitopes derived from protein amino acid sequence, and a Leishmania antigenic extract (SLA) were used as antigens. A total of 215 paired urine and serum samples were evaluated, and results showed that, when serum was employed as an analyte, rLiHyV, Peptide1, Peptide2, and SLA presented a sensitivity of 85 %, 29 %, 58 %, and 31 %, respectively, and a specificity of 97.5 %, 98 %, 100 %, and 97.5 %, respectively, in the diagnosis of TL. When urine was used, rLiHyV, Peptide1, Peptide2, and SLA presented a sensitivity of 95 %, 74 %, 67 %, and 52 %, respectively, and a specificity of 100 %, 99 %, 98 %, and 86 %, respectively. In conclusion, preliminary data suggest that urine could be considered as an alternative biological sample for the detection of TL cases.
Assuntos
Anticorpos Antiprotozoários , Antígenos de Protozoários , Ensaio de Imunoadsorção Enzimática , Leishmania , Leishmaniose Cutânea , Proteínas de Protozoários , Proteínas Recombinantes , Sensibilidade e Especificidade , Humanos , Ensaio de Imunoadsorção Enzimática/métodos , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/urina , Proteínas de Protozoários/urina , Proteínas de Protozoários/imunologia , Antígenos de Protozoários/urina , Antígenos de Protozoários/imunologia , Leishmania/imunologia , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/urina , Adulto , Feminino , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/urina , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Adolescente , Idoso , Urina/química , Urina/parasitologia , Criança , Pré-Escolar , Epitopos de Linfócito B/imunologiaRESUMO
The pathological manifestation of the inflammatory process primarily stems from the heightened release of pro-inflammatory cytokines, with IL-1ß standing out as a pivotal cytokine. The excessive presence of IL-1ß disrupts immune signaling, thereby assuming a pathogenic and exacerbating role in the pathophysiology of numerous inflammatory diseases. Regulating IL-1ß levels becomes crucial, and the IL-1Ra molecule serves this purpose by binding to the IL-1R1 receptor, thereby impeding the binding of IL-1ß. Several pharmaceuticals have entered the market, aiming to neutralize IL-1ß's biological function through diverse mechanisms. However, the existing IL-1ß inhibitors are recombinant proteins, characterized by a high production cost and limited stability. Therefore, this study aimed to predict a peptide, named DAP1-2, based on the IL-1Ra molecule. DAP1-2 was designed to attenuate responses triggered by IL-1ß by blocking the IL-1R1 receptor. The selection of amino acids from the IL-1Ra molecule (PDB: I1RA) that interact with the three domains of the IL-1R1 receptor was performed using Swiss PDB Viewer. After prediction, chemical synthesis was made using the Fmoc-Synthesis technique. The efficacy of DAP1-2 was assessed using RAW 264.7 cells, which were exposed to LPS (5 µg/mL) for 24 h to induce IL-1ß expression and treated with the peptides in different concentrations. IL-1ß levels were assessed using ELISA, and the gene expression of IL-1ß was measured by RT-qPCR, additionally to the viability test. Results revealed a significant reduction in IL-1ß levels and gene expression in cells stimulated by LPS and treated with DAP1-2 in different concentrations. Furthermore, the MTT assay confirmed the nontoxic nature of the peptides on the cell lineage. This alternative approach shows promise as an IL-1 inhibitor, due to the stability, ease of production, and cost-effectiveness provided by the use of synthetic peptides.
Assuntos
Interleucina-1beta , Receptores Tipo I de Interleucina-1 , Interleucina-1beta/metabolismo , Animais , Camundongos , Receptores Tipo I de Interleucina-1/metabolismo , Receptores Tipo I de Interleucina-1/antagonistas & inibidores , Humanos , Peptídeos/farmacologia , Células RAW 264.7 , Proteína Antagonista do Receptor de Interleucina 1/farmacologia , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Ligação Proteica , Lipopolissacarídeos/imunologiaRESUMO
Improving the diagnostic technology used to detect tegumentary leishmaniasis (TL) is essential in view of it being a widespread, often neglected tropical disease, with cases reported from the Southern United States to Northern Argentina. Recombinant proteins, recombinant multiepitope proteins, and synthetic peptides have been extensively researched and used in disease diagnosis. One of the benefits of applying these antigens is a measurable increase in sensitivity and specificity, which improves test accuracy. The present review aims to describe the use of these antigens and their diagnostic effectiveness. With that in mind, a bibliographic survey was conducted on the PudMed platform using the search terms "tegumentary leishmaniasis" AND "diagno", revealing that recombinant proteins have been described and evaluated for their value in TL diagnosis since the 1990s. However, there was a spike in the number of publications using all of the antigens between 2013 and 2022, confirming an expansion in research efforts to improve diagnosis. Moreover, all of the studies involving different antigens had promising results, including improved sensitivity and specificity. These data recognize the importance of doing research with new technologies focused on developing quick, more effective diagnostic kits as early diagnosis facilitates treatment.
Assuntos
Antígenos de Protozoários , Leishmaniose Cutânea , Proteínas Recombinantes , Antígenos de Protozoários/imunologia , Humanos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/biossíntese , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/imunologia , Testes Imunológicos/métodosRESUMO
Development of therapeutic agents that have fewer adverse effects and have higher efficacy for diseases, such as cancer, metabolic disorders, neurological diseases, infections, cardiovascular diseases, and respiratory diseases, are required. Recent studies have focused on identifying novel sources for pharmaceutical molecules to develop therapies against these diseases. Among the sources for potentially new therapies, animal venom-derived molecules have generated much interest. Various animal venom-derived proteins and peptides have been isolated, identified, synthesized, and tested to develop drugs. Venom-derived peptides have several biomedical properties, such as proapoptotic, cell migration, and autophagy regulation activities in cancer cell models; induction of vasodilation by nitric oxide and regulation of angiotensin II; modification of insulin response by controlling calcium and potassium channels; regulation of pain receptor activity; modulation of immune cell activity; alteration of motor neuron activity; degradation or inhibition of ß-amyloid plaque formation; antibacterial, antifungal, antiviral, and antiprotozoal activities; increase in sperm motility and potentiation of erectile function; reduction of intraocular pressure; anticoagulation, fibrinolytic, and antithrombotic activities; etc. This systematic review compiles these biomedical properties and potential biomedical applications of synthesized animal venom-derived peptides reported in the latest research. In addition, the limitations and areas of opportunity in this research field are discussed so that new studies can be developed based on the data presented.
Assuntos
Motilidade dos Espermatozoides , Peçonhas , Animais , Masculino , Peptídeos/farmacologia , Angiotensina IIRESUMO
Staphylococcus aureus forms biofilms, a structure that protects bacterial cells, conferring more resistance to difficult treatment. Synthetic peptides surge as an alternative to overcome the biofilm of multidrug-resistant pathogens. Mo-CBP3-PepI, when combined with Ciprofloxacin, reduced preformed S. aureus biofilm by 50% at low concentrations (0.2 and 6.2 µg. mL-1, respectively). The goal of this study was to evaluate the proteomic profile of biofilms after treatment with the Mo-CBP3-PepI combined with ciprofloxacin. Here, proteomic analysis confirmed with more depth previously described mechanisms and revealed changes in the accumulation of proteins related to DNA and protein metabolism, cell wall biosynthesis, redox metabolism, quorum sensing, and biofilm formation. Some proteins related to DNA and protein metabolism were reduced, while other proteins, like redox system proteins, disappeared in Ciprofloxacin+Mo-CBP3-PepI treatment. Our results indicated a synergistic effect of these two molecules with several mechanisms against S. aureus biofilm and opened new doors for combined treatments with other drugs.
Assuntos
Ciprofloxacina , Infecções Estafilocócicas , Humanos , Ciprofloxacina/farmacologia , Staphylococcus aureus , Proteômica , Biofilmes , DNARESUMO
Naegleria fowleri is an etiological agent that generates primary amoebic meningoencephalitis; unfortunately, no effective treatment or vaccine is available. The objective of this work was to determine the immunoprotective response of two vaccine antigens, as follows: (i) the polypeptide band of 19 kDa or (ii) a predicted immunogenic peptide from the membrane protein MP2CL5 (Smp145). Both antigens were administered intranasally in mice using cholera toxin (CT) as an adjuvant. The survival rate and immune response of immunized mice with both antigens and challenged with N. fowleri trophozoites were measured in the nose-associated lymphoid tissue (NALT) and nasal passages (NPs) by flow cytometry and enzyme-linked immunosorbent assay (ELISA). We also determined the immunolocalization of both antigens in N. fowleri trophozoites by confocal microscopy. Immunization with the polypeptide band of 19 kDa alone or coadministered with CT was able to confer 80% and 100% of protection, respectively. The immunization with both antigens (alone or coadministered with CT) showed an increase in T and B lymphocytes. In addition, there was an increase in the expression of integrin α4ß1 and IgA in the nasal cavity of protected mice, and the IgA, IgG, and IgM levels were increased in serum and nasal washes. The immunolocalization of both antigens in N. fowleri trophozoites was observed in the plasma membrane, specifically in pseudopod-like structures. The MP2CL5 antigens evaluated in this work were capable of conferring protection which would lead us to consider them as potential candidates for vaccines against meningitis caused by N. fowleri.
Assuntos
Meningite , Naegleria fowleri , Vacinas , Animais , Camundongos , Toxina da Cólera , Imunidade , Imunoglobulina ARESUMO
We report the characterization of the three-dimensional structure of the CEMP1-p1 peptide [MGTSSTDSQQAQHRRCSTSN: corresponding to residues 1-20 of the N-terminus of cementum protein 1 (CEMP1)]. This peptide imitates the capacity of CEMP1 to stimulate hydroxyapatite (HA) crystal nucleation and growth, and promotes the differentiation of periodontal ligament cells into a cementoblastic phenotype. Additionally, in experimental models of critical-sized calvarial defects in Wistar rats, CEMP1-p1 has shown osteogenic properties that enhanced the physiological deposition and maturation of newly formed bone. In this work, studies of CEMP1-p1 by circular dichroism (CD) and nuclear magnetic resonance (NMR) were performed in trifluoroethanol D2 (TFED2) and aqueous solution to determine the 3D structure of the peptide. Using the 3D model, experimental data from HA crystals formation and calcium fluorescence emission, we explain the biological mechanisms involved in CEMP1-p1 activity to promote calcium recruitment and its affinity to HA crystals. This information is valuable because it proposes, for the first time, a plausible molecular mechanism during the mineralization process, from a specific cementum protein-derived peptide.
Assuntos
Cálcio , Cemento Dentário , Ratos , Animais , Ratos Wistar , Peptídeos/química , Espectroscopia de Ressonância MagnéticaRESUMO
Rickettsia rickettsii is the etiological agent of Rocky Mountain spotted fever, which is an important tick-borne zoonosis and, in Brazil, it causes Brazilian spotted fever, which has high lethality rate. This study aimed to evaluate a synthetic peptide corresponding to a segment of the outer membrane protein A (OmpA) as an antigen in a serological test for the diagnosis of rickettsial infections. The amino acid sequence of the peptide was selected by predicting B cell epitopes using B Cell Epitope Prediction (Immune Epitope Database and Analysis Resource) and Epitopia and OmpA sequences of Rickettsia rickettsii strain 'Brazil' and Rickettsia parkeri strains 'Maculatum 20' and 'Portsmouth'. A peptide with amino acid sequence common to both Rickettsia species was synthesized and arbitrarily named OmpA-pLMC. To evaluate this peptide in enzyme-linked immunosorbent assay (ELISA), serum samples of capybara (Hydrochoerus hydrochaeris), horse (Equus caballus), and opossum (Didelphis albiventris) that had been previously tested by indirect immunofluorescence assay (IFA) for rickettsial infection were separated into IFA-positive and IFA-negative groups and used in the assay. There were no significant differences in ELISA optical density (OD) values between IFA-positive and IFA-negative groups with horse samples. The mean OD values were significantly higher in the IFA-positive capybara serum samples (IFA-pos vs. IFA-neg = 2.389 ± 0.761 vs. 1.760 ± 0.840). However, receiver operating characteristic (ROC) curve analysis did not show significant diagnostic parameters. On the other hand, 12 out of 14 (85.7%) opossum samples of the IFA-positive group showed reactivity in ELISA, and this was significantly higher than of the IFA-negative group (0.7196 ± 0.440 vs. 0.2318 ± 0.098, respectively; 85.7% sensitivity, 100% specificity). Therefore, our results show that OmpA-pLMC has a potential to be used in immunodiagnostic assays to detect spotted fever group rickettsial infections.
Assuntos
Didelphis , Doenças dos Cavalos , Infecções por Rickettsia , Rickettsia , Febre Maculosa das Montanhas Rochosas , Doenças dos Roedores , Cavalos , Animais , Roedores , Infecções por Rickettsia/diagnóstico , Infecções por Rickettsia/veterinária , Febre Maculosa das Montanhas Rochosas/microbiologia , Febre Maculosa das Montanhas Rochosas/veterinária , Rickettsia rickettsii , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Cavalos/diagnóstico , Doenças dos Roedores/microbiologiaRESUMO
Mycobacterium tuberculosis is one of the most successful pathogens affecting humans, being the main cause of tuberculosis. It accounts for most infectious agent-related deaths worldwide; it has been estimated that a third of the world's population are bacillus carriers. This pathogen's evolutionary adaptation is mainly due to its ability to block a host's immune system by preventing it using an effective immune response in cases of active tuberculosis. Peptide-based synthetic vaccines represent an alternative for counteracting tuberculosis; however, although peptide antigens can be identified, they are not recognised by a host's immune system. An approach using dendritic cells as immunomodulating agents for increasing synthetic peptides' antigenic capacity has thus been advanced. Dendritic cells obtained from IL to 4- and GM-CSF-treated peripheral blood mononuclear cells were pulsed with synthetic Mtb protein peptides which have been reported as participating in mycobacteria-host interactions; their amino acid sequences were modified to improve MHC-II coupling and thus increase their recognition by a host's immune system. pMHC-II/TCR interaction triggered a lymphocyte response which controlled Mtb intracellular growth in infected macrophages. This work has been aimed at contributing to understanding dendritic cells' role in Mycobacterium tuberculosis protein peptide antigen presentation, thereby increasing individuals' immune response as a means of controlling the disease.
Assuntos
Mycobacterium tuberculosis , Tuberculose , Humanos , Leucócitos Mononucleares , Peptídeos/química , Macrófagos , Células DendríticasRESUMO
Background: Acute lymphoblastic leukemia (ALL) is still incurable hematologic neoplasia in an important percentage of patients. Therefore, new therapeutic approaches need to be developed. Methods: To evaluate the cellular effect of cell-penetrating peptides (C-PP) on leukemia cells, Jurkat cells -a model of ALL were exposed to increasing concentration (50-500 µM) Aß25-35, R7-G-Aß25-35 and Aß25-35-G-R7 peptide for 24 h. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry (FC), and fluorescent microscopy (FM) analysis were used to assess metabolic viability, cell cycle and proliferation, mitochondria functionality, oxidative stress, and cell death markers. Results: We report for the first time that the R7-G-Aß25-35, but not Aß25-35 peptide, induced selective cell death in Jurkat cells more efficiently than the Aß25-35-G-R7 peptide. Indeed, R7-G-Aß25-35 (200 µM) altered the metabolic activity (-25%), arrested the cell cycle in the G2/M-phase (15%), and induced a significant reduction of cellular proliferation (i.e., -74% reduction of Ki-67 nuclei reactivity). Moreover, R7-G-Aß25-35 induced the dissipation of mitochondrial membrane potential (ΔΨm, 51%) and produced an important amount of reactive oxygen species (ROS, 75% at 8 h) in Jurkat cells. The exposure of cells to antioxidant/cytoprotectant N-acetylcysteine (NAC) did not prevent R7-G-Aß25-35 from a loss of ΔΨm in Jurkat cells. The peptide was also unable to activate the executer CASPASE-3, thereby preserving the integrity of the cellular DNA corroborated by the fact that the caspase-3 inhibitor NSCI was unable to protect cells from R7-G-Aß25-35 -induced cell damage. Further analysis showed that the R7-G-Aß25-35 peptide is specifically localized at the outer mitochondria membrane (OMM) according to colocalization with the protein translocase TOMM20. Additionally, the cytotoxic effect of the poly-R7 peptide resembles the toxic action of the uncoupler FCCP, mitocan oligomycin, and rotenone in Jurkat cells. Importantly, the R7-G-Aß25-35 peptide was innocuous to menstrual mesenchymal stromal cells (MenSC) -normal non-leukemia proliferative cells. Conclusion: Our findings demonstrated that the cationic Aß peptide possesses specific anti-leukemia activity against Jurkat cells through oxidative stress (OS)- and CASPASE-3-independent mechanism but fast mitochondria depolarization.
RESUMO
Coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is considered one of the worst pandemic outbreaks worldwide. This ongoing pandemic urgently requires rapid, accurate, and specific testing devices to detect the virus. We report a simple electrochemical biosensor based on a highly specific synthetic peptide to detect SARS-CoV-2 Spike protein. Unlike other reported electrochemical biosensors involving nanomaterials or complex approaches, our electrochemical platform uses screen-printed gold electrodes functionalized with the thiolated peptide, whose interaction with the Spike protein is directly followed by Electrochemical Impedance Spectroscopy. The electrochemical platform was Spike protein concentration-dependent, with high sensitivity and reproducibility and a limit of detection of 18.2 ng/mL when tested in Spike protein commercial solutions and 0.01 copies/mL in lysed SARS-CoV-2 particles. The label-free biosensor successfully detected the Spike protein in samples from infected patients straightforwardly in only 15 min. The simplicity of the proposed format combined with an on-demand designed peptide opens the path for detecting other pathogen-related antigens.
Assuntos
Técnicas Biossensoriais , COVID-19 , Técnicas Biossensoriais/métodos , COVID-19/diagnóstico , Técnicas Eletroquímicas/métodos , Humanos , Peptídeos , Reprodutibilidade dos Testes , SARS-CoV-2 , Glicoproteína da Espícula de CoronavírusRESUMO
TnP is a family of patented synthetic peptides which is in a preclinical development stage with valuable potential therapeutic indication for multiple sclerosis (MS), an autoimmune demyelinating disease of the central nervous system (CNS). The use of a preclinical animal model, such as experimental autoimmune encephalomyelitis (EAE) has deepened our knowledge of the immunomodulatory functions of TnP as a drug. We have shown that TnP possesses a disease suppressive function in EAE, ameliorating disease severity by 40% and suppressing the accumulation of T helper (Th)1- and Th17-producing lymphocytes (by 55% and 60%, respectively) in CNS along with activated microglia/macrophages populations (by 33% and 50%, respectively), and also conferred a protective effect anticipating the remyelination process to day 66 compared to day 83 of untreated cuprizone-mice. Here we expanded our knowledge about its effects compared with current first-line disease-modifying therapies (DMT). We demonstrated that prophylactic treatment with TnP generated similar protection to betaseron (30%) or was more effective than glatiramer (44% versus 6%) or fingolimod (50% versus 19%) against the development of clinical symptoms. Although TnP controlled the leukocyte infiltration (87% versus 82%) into demyelinated areas of the spinal cord in the same way as betaseron and fingolimod, it was more effective (72% to 78% decrease) in the long-term control of neuronal degeneration compared to them. Also, when compared to glatiramer, TnP was more efficient in reversing leukocytes infiltration into the spinal cord (55% versus 24%), as well as induced a higher percentage of regulatory cells in spleen (2.9-fold versus 2.3-fold increase over vehicle-treated EAE mice) an in the spinal cord (8-fold versus 6-fold increase over vehicle-treated EAE mice). This specialized TnP profile for inducing immune tolerance and neuronal regeneration has significant therapeutic potential for the treatment of MS and other autoimmune diseases.
Assuntos
Encefalomielite Autoimune Experimental , Esclerose Múltipla , Animais , Cloridrato de Fingolimode/uso terapêutico , Acetato de Glatiramer/uso terapêutico , Interferon beta-1b/efeitos adversos , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/tratamento farmacológico , Peptídeos/uso terapêuticoRESUMO
Oral immunization with the choleric toxin (CT) elicits a high level of protection against its enterotoxin activities and can control cholera in endemic settings. However, the complete B-cell epitope map of the CT that is responsible for protection remains to be clarified. A library of one-hundred, twenty-two 15-mer peptides covering the entire sequence of the three chains of the CT protein (CTP) was prepared by SPOT synthesis. The immunoreactivity of membrane-bound peptides with sera from mice vaccinated with an oral inactivated vaccine (Schankol™) allowed the mapping of continuous B-cell epitopes, topological studies, multi-antigen peptide (MAP) synthesis, and Enzyme-Linked Immunosorbent Assay (ELISA) development. Eighteen IgG epitopes were identified; eight in the CTA, three in the CTB, and seven in the protein P. Three V. cholera specific epitopes, Vc/TxA-3, Vc/TxB-11, and Vc/TxP-16, were synthesized as MAP4 and used to coat ELISA plates in order to screen immunized mouse sera. Sensitivities and specificities of 100% were obtained with the MAP4s of Vc/TxA-3 and Vc/TxB-11. The results revealed a set of peptides whose immunoreactivity reflects the immune response to vaccination. The array of peptide data can be applied to develop improved serological tests in order to detect cholera toxin exposure, as well as next generation vaccines to induce more specific antibodies against the cholera toxin.
Assuntos
Vacinas contra Cólera , Cólera , Vibrio cholerae , Animais , Camundongos , Vibrio cholerae/metabolismo , Toxina da Cólera/metabolismo , Epitopos de Linfócito B , Mapeamento de Epitopos , Ensaio de Imunoadsorção Enzimática , Anticorpos AntibacterianosRESUMO
TnP is a family of patented synthetic peptides which is in a preclinical development stage with valuable potential therapeutic indication for multiple sclerosis (MS), an autoimmune demyelinating disease of the central nervous system (CNS). The use of a preclinical animal model, such as experimental autoimmune encephalomyelitis (EAE) has deepened our knowledge of the immunomodulatory functions of TnP as a drug. We have shown that TnP possesses a disease suppressive function in EAE, ameliorating disease severity by 40% and suppressing the accumulation of T helper (Th)1- and Th17-producing lymphocytes (by 55% and 60%, respectively) in CNS along with activated microglia/macrophages populations (by 33% and 50%, respectively), and also conferred a protective effect anticipating the remyelination process to day 66 compared to day 83 of untreated cuprizone-mice. Here we expanded our knowledge about its effects compared with current first-line disease-modifying therapies (DMT). We demonstrated that prophylactic treatment with TnP generated similar protection to betaseron (30%) or was more effective than glatiramer (44% versus 6%) or fingolimod (50% versus 19%) against the development of clinical symptoms. Although TnP controlled the leukocyte infiltration (87% versus 82%) into demyelinated areas of the spinal cord in the same way as betaseron and fingolimod, it was more effective (72% to 78% decrease) in the long-term control of neuronal degeneration compared to them. Also, when compared to glatiramer, TnP was more efficient in reversing leukocytes infiltration into the spinal cord (55% versus 24%), as well as induced a higher percentage of regulatory cells in spleen (2.9-fold versus 2.3-fold increase over vehicle-treated EAE mice) an in the spinal cord (8-fold versus 6-fold increase over vehicle-treated EAE mice). This specialized TnP profile for inducing immune tolerance and neuronal regeneration has significant therapeutic potential for the treatment of MS and other autoimmune diseases.
RESUMO
Thirty-five peptides selected from functionally-relevant SARS-CoV-2 spike (S), membrane (M), and envelope (E) proteins were suitably modified for immunising MHC class II (MHCII) DNA-genotyped Aotus monkeys and matched with HLA-DRß1* molecules for use in humans. This was aimed at producing the first minimal subunit-based, chemically-synthesised, immunogenic molecules (COLSARSPROT) covering several HLA alleles. They were predicted to cover 48.25% of the world's population for 6 weeks (short-term) and 33.65% for 15 weeks (long-lasting) as they induced very high immunofluorescent antibody (IFA) and ELISA titres against S, M and E parental native peptides, SARS-CoV-2 neutralising antibodies and host cell infection. The same immunological methods that led to identifying new peptides for inclusion in the COLSARSPROT mixture were used for antigenicity studies. Peptides were analysed with serum samples from patients suffering mild or severe SARS-CoV-2 infection, thereby increasing chemically-synthesised peptides' potential coverage for the world populations up to 62.9%. These peptides' 3D structural analysis (by 1H-NMR acquired at 600 to 900 MHz) suggested structural-functional immunological association. This first multi-protein, multi-epitope, minimal subunit-based, chemically-synthesised, highly immunogenic peptide mixture highlights such chemical synthesis methodology's potential for rapidly obtaining very pure, highly reproducible, stable, cheap, easily-modifiable peptides for inducing immune protection against COVID-19, covering a substantial percentage of the human population.
Assuntos
Vacinas contra COVID-19/imunologia , COVID-19/imunologia , Proteínas do Envelope de Coronavírus/imunologia , Proteínas M de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas de Subunidades Antigênicas/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Aotidae , COVID-19/prevenção & controle , Cadeias HLA-DRB1/genética , Humanos , Peptídeos/imunologia , SARS-CoV-2/imunologiaRESUMO
Knowledge of immunodominant B-cell epitopes is essential to design powerful diagnostic strategies aiming for antibody detection. Outstanding progress in computational prediction has achieved a significant contribution to the biomedical fields, including immunodiagnosis. In silico analysis may have an even more important role when information concerning antigens from etiologic agents of neglected diseases, such as leprosy, is scarce. The aim of this study was to provide mapping of B-cell epitopes from two Mycobacterium leprae-derived antigens (Ag85B and ML2055), confirm their antigenicity, and to assess the ability of in silico immunoinformatics tools to accurately predict them. Linear B-cell epitopes predicted by ABCpred and SVMTrip servers were compared to antigenic regions of synthetic overlapping peptides that exhibited reactivity to antibodies from patients with leprosy. Our in vitro results identified several immunodominant regions that had also been indicated by in silico prediction, providing agreement between experimental and simulated data. After chemical synthesis, we used enzyme-linked immunosorbent assays to determine the effectiveness of the first identified sequence (GTNVPAEFLENFVHG) which had 72 % sensitivity and 78 % specificity (AUC = 0.79) while the second one (PVSSEAQPGDPNAPS) had 72 % sensitivity and 93.8 % specificity (AUC = 0.85). Using dot blotting, an easy-to-read visual test, both peptides could distinguish sera from patients with leprosy from those with tuberculosis and from sera of healthy volunteers. Our findings suggest that these synthetic peptides, with some refinement, may be useful as serological diagnostic antigens for leprosy. In addition, it was displayed that immunoinformatics provides reliable information for mapping potential B-cell epitopes for development of peptide-based diagnostic assays for neglected diseases.
Assuntos
Antígenos de Bactérias/imunologia , Mapeamento de Epitopos/métodos , Epitopos de Linfócito B/imunologia , Hanseníase/diagnóstico , Testes Sorológicos/métodos , Adulto , Anticorpos Antibacterianos/imunologia , Feminino , Humanos , Hanseníase/sangue , Hanseníase/imunologia , Masculino , Pessoa de Meia-Idade , Mycobacterium lepraeRESUMO
Successful Plasmodium falciparum invasion of red blood cells includes the orderly execution of highly specific receptor-ligand molecular interactions between the parasite's proteins and the red blood cell membrane proteins. There is a growing need for elucidating receptor-ligand pairings, which will help in understanding the parasite's biology and provide the fundamental basis for developing prophylactic or therapeutic alternatives leading to mitigating or eliminating this type of malaria. We have thus used Plasmodium falciparum RH5 - derived peptides and ghost red blood cell proteins in synthetic peptide affinity capture assays to identify important host receptors used by Plasmodium spp. in the invasion of red blood cells. LC-MS/MS analysis confirmed the extensively described interaction between PfRH5 and the basigin receptor on the red blood cell membrane. As shown here, tagged synthetic peptides displaying high binding ability to erythrocytes can be used to identify receptors present in protein extracts from ghost red blood cells via affinity capture and LC-MS/MS. SIGNIFICANCE: The article describes a novel approach for identifying red blood cell receptors based on the ability of synthetic peptides having high red blood cell binding capacity to capture Plasmodium spp. receptors on proteins extracted from ghost red blood cells. Specifically, novel methods to identify Plasmodium falciparum reticulocyte binding protein homolog 5 PfRH5 and basigin interaction using a combination of affinity capture and LC-MS/MS assays is described. Identification of these host RBC receptors interacting with malarial parasite proteins is of utmost importance in studying the disease's pathogenesis and will provide crucial information in understanding the parasite's biology. In addition, data from these studies can be used to identify potential therapeutic target(s) to mitigate or eliminate this debilitating disease.
Assuntos
Eritrócitos/parasitologia , Plasmodium falciparum , Proteínas de Transporte/metabolismo , Cromatografia Líquida , Humanos , Peptídeos , Ligação Proteica , Proteínas de Protozoários/metabolismo , Espectrometria de Massas em TandemRESUMO
Nile tilapia (Oreochromis niloticus) is a freshwater fish, which is extensively cultivated worldwide and constitutes one of the model species for the study of fish immunology. Monoclonal antibodies are very advantageous molecular tools for studying teleost immune system. Specifically, monoclonal antibodies that react with immunoglobulins are used successfully in the study of the humoral immune response of several fish species. In the present study, we produced and characterized a monoclonal antibody against tilapia IgM heavy chain using a peptide-based strategy. The peptide sequence was selected from the surface-exposed region between CH3-CH4 domains. The specificity of the polyclonal serum and the hybridoma culture supernatant obtained by immunization with the peptide conjugated to keyhole limpet hemocyanin were evaluated by western blotting, both showing reactivity against tilapia serum IgM. The purified mAb was able to recognize secreted IgM by western blotting and ELISA and membrane IgM by flow cytometry. We also demonstrated that the antibody doesn't cross-react with a recombinant IgT fragment. This tool allowed us to study for the first time the stimulation of mucosal immunity after Pituitary Adenylate Cyclase Activating Polypeptide administration. Overall, the results demonstrated the utility of this mAb to characterize humoral immune response in O. niloticus.
Assuntos
Anticorpos Monoclonais/imunologia , Ciclídeos/imunologia , Proteínas de Peixes/imunologia , Imunidade Humoral , Cadeias Pesadas de Imunoglobulinas/imunologia , Imunoglobulina M/imunologia , Sequência de Aminoácidos , Animais , Alinhamento de SequênciaRESUMO
Foot-and-mouth disease (FMD) is one of the most contagious veterinary viral diseases known, having economic, social and potentially devastating environmental impacts. The vaccines currently being marketed/sold around the world for disease control and prevention in bovines do not stimulate the production of antibodies having crossed reactions to different serotypes. This means that if an animal becomes infected by a serotype which has not been included in a vaccine then it will develop the disease. Synthetic peptide vaccines represent a safer option and (depending on the design) can stimulate antibodies protecting against different variants. Based on the forgoing, this work was aimed at evaluating FMDV VP1, VP2 and VP3 protein-derived, modified and chemically-synthesised peptides' ability to induce an immune response for developing a vaccine contributing towards controlling the disease. VP1, VP2 and VP3 proteins' conserved regions were selected for this. Peptides from these regions were chemically synthesised; binding assays were then carried out for ascertaining whether they were involved in BHK-21 cell binding. Selected peptides' structure and location were studied. Peptides which did bind were modified and formulated with Montanide ISA 70 adjuvant; 17 animals were immunised twice with the formulation. The animals were genotyped by amplifying the BoLA-DRB3.2 gene. Blood samples were taken from 17 cattle on day 43 post-first immunisation for studying the formulation's immunogenicity. The sera were used in ELISA, immunofluorescence, flow cytometry, immunoadsorption and seroneutralisation assays. The A24 Cruzeiro and O1 Campos virus serotypes were used for these assays. The results revealed that even though protein exposure and 3D structure might be different amongst serotypes, the antibodies so produced could inhibit virus entry to cells, thereby showing the selected peptides' in vitro protection-inducing ability.
Assuntos
Vírus da Febre Aftosa , Febre Aftosa , Peptídeos , Vacinas Virais , Animais , Anticorpos Antivirais , Proteínas do Capsídeo/genética , Bovinos , Febre Aftosa/prevenção & controle , Vírus da Febre Aftosa/imunologiaRESUMO
Metallothioneins (MTs) have been identified in a wide variety of organisms from bacteria to humans. The biological functions of these MTs have a key role in metalloregulatory metabolism and its expression is induced in response to different stimuli, particularly by divalent metal cations. Also, the action of MTs have been implicated in the survival of pathogens in presence of microbicidal concentration of divalent cations, which allows the establishment of the infection. Trichomonas vaginalis is a protozoan parasite that adapts to the microenvironment of the male urogenital tract, where cations such as zinc (Zn2+) and cadmium (Cd2+) are present. Nevertheless, the molecular mechanisms of metal tolerance and homeostasis is not yet dilucidated in this parasite. In this study, we have identified 4 potential MT-like sequences (tvmt´s) in T. vaginalis genome. Because tvmt-2, -3, and -4 corresponds to truncated partial genes, we characterized the trichomonad tvmt-1 gene. The bioinformatic analyses and the predicted protein (TvMT-1) show similar properties to the reported in other MTs. The expression patterns of tvmt-1 in the presence of several divalent cations (Fe2+, Mn2+, Zn2+ and Cd2+) were analyzed and we demonstrated that Cd2+ induce significantly their expression. By indirect immunofluorescence assays, we corroborated this positive regulation of TvMT-1 in the cytoplasm of parasites grown in the presence of Cd2+. The tvmt-1 promoter contains putative metal responsive elements, which are probably the responsible for the Cd2+-dependent expression of this gene. Our results suggest that tvmt-1 gene encode a metallothionein that may be responsible for the homeostatis and detoxification of Cd+2 in T. vaginalis.