RESUMO
There is an increasing attention to the emerging health problem represented by the clinical and functional long-term consequences of SARS-CoV-2 infection, referred to as postacute COVID-19 syndrome. Clinical, radiographic, and autopsy findings have shown that a high rate of fibrosis and restriction of lung function are present in patients who have recovered from COVID-19. Patients with active TB, or those who have recovered from it, have fibrotic scarred lungs and, consequently, some degree of impaired respiratory function. Helminth infections trigger predominantly type 2 immune responses and the release of regulatory and fibrogenic cytokines, such as TGF-ß. Here, we analyze the possible consequences of the overlapping of pulmonary fibrosis secondary to COVID-19 and tuberculosis in the setting of sub-Saharan Africa, the region of the world with the highest prevalence of helminth infection.
RESUMO
Lipids, glycolipids and lipopeptides derived from Mycobacterium tuberculosis (Mtb) are presented to T cells by monomorphic molecules known as CD1. This is the case of the Mtb-specific sulfoglycolipid Ac2SGL, which is presented by CD1b molecules and is recognized by T cells found in tuberculosis (TB) patients and in individuals with latent infections. Our group, using filamentous phage display technology, obtained two specific ligands against the CD1b-Ac2SGL complex: (i) a single chain T cell receptor (scTCR) from a human T cell clone recognizing the CD1b-AcSGL complex; and (ii) a light chain domain antibody (dAbκ11). Both ligands showed lower reactivity to a synthetic analog of Ac2SGL (SGL12), having a shorter acyl chain as compared to the natural antigen. Here we put forward the hypothesis that the CD1b endogenous spacer lipid (EnSpacer) plays an important role in the recognition of the CD1b-Ac2SGL complex by specific T cells. To support this hypothesis we combined: (a) molecular binding assays for both the scTCR and the dAbκ11 antibody domain against a small panel of synthetic Ac2SGL analogs having different acyl chains, (b) molecular modeling of the CD1b-Ac2SGL/EnSpacer complex, and (c) modeling of the interactions of this complex with the scTCR. Our results contribute to understand the mechanisms of lipid presentation by CD1b molecules and their interactions with T-cell receptors and other specific ligands, which may help to develop specific tools targeting Mtb infected cells for therapeutic and diagnostic applications.
Assuntos
Antígenos de Bactérias/imunologia , Antígenos CD1/imunologia , Modelos Moleculares , Mycobacterium tuberculosis/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Antígenos CD1/genética , Humanos , Proteínas Recombinantes/imunologiaAssuntos
Coinfecção , Infecções por Coronavirus , Helmintos , Pandemias , Pneumonia Viral , África Subsaariana/epidemiologia , Animais , Betacoronavirus , COVID-19 , Humanos , SARS-CoV-2RESUMO
Tuberculosis (TB) remains an important cause of mortality and morbidity. The TB vaccine, BCG, is not fully protective against the adult form of the disease and is unable to prevent its transmission although it is still useful against severe childhood TB. Hence, the search for new vaccines is of great interest. In a previous study, we have shown that proteoliposomes obtained from Mycobacterium smegmatis (PLMs) induced cross reactive humoral and cellular response against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLMs, a murine model of progressive pulmonary TB was used. Animals immunized with PLMs with and without alum (PLMs/PLMsAL respectively) showed protection compared to non-immunized animals. Mice immunized with PLMsAL induced similar protection as that of BCG. Animals immunized with BCG, PLMs and PLMsAL showed a significant decrease in tissue damage (percentage of pneumonic area/lung) compared to non-immunized animals, with a more prominent effect in BCG vaccinated mice. The protective effect of the administration of PLMs in mice supports its future evaluation as experimental vaccine candidate against Mtb.
Assuntos
Mycobacterium smegmatis/imunologia , Proteolipídeos/imunologia , Vacinas contra a Tuberculose , Tuberculose Pulmonar/prevenção & controle , Adjuvantes Imunológicos , Compostos de Alúmen , Animais , Vacina BCG , Carga Bacteriana , Modelos Animais de Doenças , Progressão da Doença , Masculino , Camundongos Endogâmicos BALB C , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/isolamento & purificação , Pneumonia Bacteriana/microbiologia , Pneumonia Bacteriana/patologia , Pneumonia Bacteriana/prevenção & controle , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/patologiaRESUMO
OBJECTIVE/BACKGROUND: The development of new tools capable of targeting Mycobacterium tuberculosis (Mtb)-infected cells have potential applications in diagnosis, treatment, and prevention of tuberculosis. In Mtb-infected cells, CD1b molecules present Mtb lipids to the immune system (Mtb lipid-CD1b complexes). Because of the lack of CD1b polymorphism, specific Mtb lipid-CD1b complexes could be considered as universal Mtb infection markers. 2-Stearoyl-3-hydroxyphthioceranoyl-2'-sulfate-α-α'-d-trehalose (Ac2SGL) is specific for Mtb, and is not present in other mycobacterial species. The CD1b-Ac2SGL complexes are expressed on the surface of human cells infected with Mtb. The aim of this study was to generate ligands capable of binding these CD1b-Ac2SGL complexes. METHODS: A synthetic human scFv phage antibody library was used to select phage-displayed antibody fragments that recognized CD1b-Ac2SGL using CD1b-transfected THP-1 cells loaded with Ac2SGL. RESULTS: One clone, D11-a single, light-variable domain (kappa) antibody (dAbκ11)-showed high relative binding to the Ac2SGL-CD1b complex. CONCLUSION: A ligand recognizing the Ac2SGL-CD1b complex was obtained, which is a potential candidate to be further tested for diagnostic and therapeutic applications.
Assuntos
Anticorpos Antibacterianos/imunologia , Antígenos CD1/imunologia , Glicolipídeos/imunologia , Mycobacterium tuberculosis/imunologia , Anticorpos de Cadeia Única/genética , Tuberculose/imunologia , Anticorpos Antibacterianos/genética , Antígenos CD1/genética , Bacteriófagos/genética , Bacteriófagos/metabolismo , Expressão Gênica , Humanos , Mycobacterium tuberculosis/genética , Anticorpos de Cadeia Única/imunologia , Tuberculose/microbiologiaRESUMO
TB, caused by Mycobacterium tuberculosis (MTB), is one of the major global infectious diseases. For the pandemic control, early diagnosis with sensitive and specific methods is fundamental. With the advent of bioinformatics' tools, the identification of several proteins involved in the pathogenesis of TB (TB) has been possible. In the present work, the MTB genome was explored to look for molecules with possible antigenic properties for their evaluation as part of new generation diagnostic kits based on the release of cytokines. Seven proteins from the MTB proteome and some of their combinations suited the computational test and the results suggested their potential use for the diagnosis of infection in the following population groups: Cuba, Mexico, Malaysia and sub-Saharan Africa. Our predictions were performed using public bioinformatics tools plus three computer programs, developed by our group, to facilitate information retrieval and processing.
Assuntos
Proteínas de Bactérias/imunologia , Simulação por Computador , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Tuberculose/diagnóstico , Sequência de Aminoácidos , Antígenos de Bactérias/imunologia , Sequência de Bases , Biologia Computacional , Citocinas/biossíntese , Humanos , Proteoma , Análise de Sequência de DNA , Tuberculose/imunologiaRESUMO
The development of molecules specific for M. tuberculosis-infected cells has important implications, as these tools may facilitate understanding of the mechanisms regulating host pathogen interactions in vivo. In addition, development of new tools capable to targeting M. tuberculosis-infected cells may have potential applications to diagnosis, treatment, and prevention of tuberculosis (TB). Due to the lack of CD1b polymorphism, M. tuberculosis lipid-CD1b complexes could be considered as universal tuberculosis infection markers. The aim of the present study was to display on the PIII surface protein of m13 phage, a human αß single-chain T-cell receptor molecule specific for CD1b:2-stearoyl-3-hydroxyphthioceranoyl-2´-sulfate-α-α´-D-trehalose (Ac2SGL) which is a complex presented by human cells infected with M. tuberculosis. The results showed the pIII fusion particle was successfully displayed on the phage surface. The study of the recognition of the recombinant phage in ELISA and immunohistochemistry showed the recognition of CD1b:Ac2SGL complexes and cells in human lung tissue from a tuberculosis patient respectively, suggesting the specific recognition of the lipid-CD1b complex.
Assuntos
Antígenos de Bactérias/imunologia , Antígenos CD1/imunologia , Técnicas de Visualização da Superfície Celular , Glicolipídeos/imunologia , Mycobacterium tuberculosis/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Tuberculose/imunologia , Bacteriófago M13 , Linhagem Celular , Genes Codificadores da Cadeia alfa de Receptores de Linfócitos T , Genes Codificadores da Cadeia beta de Receptores de Linfócitos T , Humanos , Pulmão/imunologia , Pulmão/microbiologia , Ativação Linfocitária , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas ViraisRESUMO
An in silico study was carried out to identify antigens for their possible collective use as vaccine candidates against diseases caused by different classes of pathogenic mycobacteria with significant clinical relevance. The genome sequences of the relevant causative agents were used in order to search for orthologous genes among them. Bioinformatics tools permitted us to identify several conserved sequences with 100% identity with no possibility of cross-reactivity to the normal flora and human proteins. Nine different proteins were characterized using the strain H37Rv as reference and taking into account their functional category, their in vivo expression and subcellular location. T and B cell epitopes were identified in the selected sequences. Theoretical prediction of population coverage was calculated for individual epitopes as well as their combinations. Several identical sequences, belonging to six proteins containing T and B cell epitopes which are not present in selected microorganisms of the normal microbial flora or in human proteins were obtained.
Assuntos
Antígenos de Bactérias/imunologia , Epitopos/imunologia , Mycobacterium tuberculosis/imunologia , Mycobacterium/imunologia , Sequência de Aminoácidos , Antígenos de Bactérias/química , Proteínas de Bactérias/química , Proteínas de Bactérias/imunologia , Vacinas Bacterianas , Sequência de Bases , Biologia Computacional , Simulação por Computador , Sequência Conservada , Epitopos/química , Genoma Bacteriano , Humanos , Mycobacterium/genética , Mycobacterium tuberculosis/genética , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Research, development, and production of vaccines are still highly dependent on the use of animal models in the various evaluation steps. Despite this fact, there are strong interests and ongoing efforts to reduce the use of animals in vaccine development. Tuberculosis vaccine development is one important example of the complexities involved in the use of animal models for the production of new vaccines. This review summarises some of the general aspects related with the use of animals in vaccine research and production, as well as achievements and challenges towards the rational use of animals, particularly in the case of tuberculosis vaccine development.