RESUMO
The persistence of new leprosy cases in endemic areas such as India, Brazil, Bangladesh, and the Philippines has encouraged studies of chemoprophylaxis among contacts of patients. Epidemiological screening tools to enable early detection of infected individuals in endemic populations would be critical to target individuals most in need of intervention. Despite decades of attempts, however, there still are no tests available for the early detection of low-level infection with Mycobacterium leprae. In this report, we describe the development of a leprosy skin test using M. leprae-specific antigens. We selected the chimeric LID-1 fusion protein, formulated to achieve maximum performance at a minimal dose, as a skin test candidate based on its ability to elicit delayed-type hypersensitivity (DTH) reactions in M. leprae immune guinea pigs in a sensitive and specific manner, i.e., with no cross-reactivity observed with other mycobacterial species. Importantly, evaluations in armadillos indicated that intradermal inoculation of formulated LID-1 could distinguish uninfected from M. leprae-infected animals manifesting with symptoms distinctly similar to the PB presentation of patients. Together, our data provide strong proof-of-concept for developing an antigen-specific skin test to detect low-level M. leprae infection. Such a test could, when applied with appropriate use of chemo- and/or immunoprophylaxis, be instrumental in altering the evolution of clinical disease and M. leprae transmission, thus furthering the objective of zero leprosy.
Assuntos
Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Hipersensibilidade Tardia , Hanseníase Paucibacilar/diagnóstico , Testes Cutâneos/métodos , Animais , Antígenos de Bactérias/farmacologia , Tatus , Proteínas de Bactérias/farmacologia , Diagnóstico Precoce , Feminino , Cobaias , Injeções Intradérmicas , Hanseníase Paucibacilar/imunologia , Mycobacterium leprae , Estudo de Prova de Conceito , Pele/efeitos dos fármacosRESUMO
Mycobacterium leprae, causative organism of leprosy, is known to counter redox stress generated by reactive oxygen species (ROS) during its survival inside host macrophages. But, the involvement of any antigenic protein(s) for countering such redox stress is still unknown. Interestingly, M. leprae HSP18, an important antigenic protein that helps in the growth and survival of M. leprae pathogen inside host macrophages, is induced under redox stress. Moreover, HSP18 also interacts with Cu2+. Copper (II) can induce redox stress via Fenton reaction. But, whether HSP18 suppresses Cu2+ mediated ROS generation, is still far from clear. Also, the effect of redox stress on its structure and function is not known. In this study, we show that HSP18 efficiently suppresses Cu2+ mediated generation of ROS and also prevents the redox mediated aggregation of a client protein (γD-crystallin). Upon exposure to substantial redox stress, irreversible perturbation in the secondary and tertiary structure of HSP18 and the tryptophan and tyrosine oxidation are evidenced. Interestingly, HSP18 retains a considerable amount of functionality even after being exposed to substantial redox stress. Perhaps, the redox scavenging ability as well as the chaperone function of HSP18 may possibly help M. leprae pathogen to counter redox stress inside host macrophages.
Assuntos
Proteínas de Bactérias/metabolismo , Cobre/metabolismo , Proteínas de Choque Térmico/metabolismo , Mycobacterium leprae/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ácido Ascórbico/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/farmacologia , Peróxido de Hidrogênio/metabolismo , Radical Hidroxila/metabolismo , Macrófagos/microbiologia , Chaperonas Moleculares/metabolismo , Mycobacterium leprae/genética , Oxirredução/efeitos dos fármacos , Proteínas Recombinantes , Tirosina/metabolismoRESUMO
Mycobacterium tuberculosis secretes a number of proteins into the extracellular milieu during growth. Several of these proteins have been associated with modulation of the host immune response. Antigen 84, or Wag31, is one such protein that is conserved among all mycobacterial species and is recognized by the sera from tuberculosis and leprosy patients. Here, we examined the effect of Wag31 on the ability of activated human T cells to produce cytokines such as IL-10, IL-17 and IFN-γ in response to combined anti-CD3 and anti-CD28 stimulation. Purified recombinant Wag31 inhibited the secretion of IL-10 and IL-17, but not IFN-γ, by human T cells stimulated with plate-bound anti-CD3 and anti-CD28 monoclonal antibodies. Furthermore, the C-terminal domain, but not the N-terminal domain, inhibited the production of IL-10 and IL-17 without a significant effect on the production of IFN-γ. These data suggest that Wag31 may modulate human T cell immune responses during tuberculosis infection through its C-terminal domain.
Assuntos
Proteínas de Bactérias/farmacologia , Citocinas/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Mycobacterium tuberculosis/imunologia , Linfócitos T/efeitos dos fármacos , Proteínas de Bactérias/química , Proteínas de Bactérias/imunologia , Células Cultivadas , Citocinas/imunologia , Relação Dose-Resposta a Droga , Humanos , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucina-10/imunologia , Interleucina-10/metabolismo , Interleucina-17/imunologia , Interleucina-17/metabolismo , Domínios Proteicos , Relação Estrutura-Atividade , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
BACKGROUND: Immunological characterization of mycobacterial peptides may help not only in the preparation of a vaccine for leprosy but also in developing in vitro T-cell assays that could perhaps be used as an in vitro correlate for treatment outcome. The main goal of this study was to evaluate the use of Mycobacterium bovis recombinant 32-kDa protein (r32-kDa) antigen-stimulated T-cell assay as a surrogate marker for treatment outcome and monitor vitamin D receptor (VDR)-mediated anti-microbial responses during multidrug therapy (MDT) in leprosy. METHODS: Newly diagnosed tuberculoid and lepromatous leprosy patients were enrolled and followed up during their course of MDT at 6 and 12 months. IFN-γ, IL-10, IL-17 and IL-23 levels in culture supernatants and expression of VDR, TLR2, LL37 and DEFB in r32-kDa-stimulated PBMCs were measured. Controls comprised household contacts (HHCs) and healthy endemic subjects (HCs). RESULTS: Significant differences were observed in the levels of IFN-γ, IL-17, IL-23, VDR and anti-microbial peptides LL37 and DEFB after treatment and when compared with that of HHCs and HCs, respectively. CONCLUSIONS: These findings suggest that responses to r32-kDa antigen reflect an improved immunological and anti-microbial response in leprosy patients during therapy, thereby indicating its potential use as an immune correlate in the treatment of leprosy patients.
Assuntos
Antígenos de Bactérias/farmacologia , Proteínas de Bactérias/farmacologia , Citocinas/imunologia , Hanseníase/imunologia , Mycobacterium bovis , Linfócitos T/imunologia , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Peptídeos Catiônicos Antimicrobianos , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Catelicidinas/imunologia , Feminino , Seguimentos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/imunologia , Humanos , Hanseníase/patologia , Masculino , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/farmacologia , Linfócitos T/patologia , Receptor 2 Toll-Like/imunologiaRESUMO
BACKGROUND: Allergic asthma is a chronic pulmonary disease characterized by a Th2 inflammatory response. The modulation of a Th2 immune response based on immune deviation to a Th1 pattern or induction and migration of regulatory T cells to the lungs constitutes one of the major therapeutic approaches that is being investigated for the treatment of allergic asthma. The potentials of Mycobacterium leprae 65-kD heat-shock protein or Toll-like receptor 9 ligand (CpG oligodeoxynucleotides) as immune modulators for the treatment of airway allergic disease have been studied individually. OBJECTIVE: Mycobacterial protein combined with CpG was used as immunotherapy for airway allergy. METHODS: Using an ovalbumin-induced asthma model, mice were sensitized and challenged, and then treated with mycobacterial heat-shock protein (Hsp65) combined with CpG. RESULTS: The treatment of mice with established allergy led to the attenuation of eosinophilia, Th2 cytokines and airway hyperresponsiveness. Hsp65 plus CpG treatment also induced an increase in OVA-specific IFN-γ levels and in the frequency of lung inflammatory monocytes. Moreover, we show that the reduction of eosinophilia and the recruitment of inflammatory monocytes to the lungs required early triggering of TLR9, IFN-γ and CCR2 by immunotherapy components. CONCLUSION: In addition to immune deviation to a Th1 response in the modulation of Th2 allergic inflammation, our findings also attribute an important role to the innate response mediated by TLR9, associated with the recruitment of CCR2-dependent monocytes. CLINICAL RELEVANCE: Our findings show that the Hsp65/CpG treatment is a promising strategy for consideration in translational studies.
Assuntos
Asma/tratamento farmacológico , Proteínas de Bactérias/farmacologia , Chaperonina 60/farmacologia , Interferon gama/imunologia , Mycobacterium leprae , Oligodesoxirribonucleotídeos/farmacologia , Receptores CCR2/imunologia , Transdução de Sinais/efeitos dos fármacos , Receptor Toll-Like 9/imunologia , Animais , Asma/genética , Asma/imunologia , Imunoterapia , Interferon gama/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Receptores CCR2/genética , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/patologia , Receptor Toll-Like 9/genéticaRESUMO
Microbial heat shock proteins (hsp) have been associated with the generation and induction of Th1-type immune responses. We tested the effects of treatment with five different microbial hsp (Mycobacterium leprae, Streptococcus pneumoniae, Helicobacter pylori, bacillus Calmette-Guérin, and Mycobacterium tuberculosis) in a murine model of allergic airway inflammation and airway hyperresponsiveness (AHR). Mice were sensitized to OVA by i.p. injection and then challenged by OVA inhalation. Hsp were administered to each group by i.p. injection before sensitization and challenge. Sensitized and challenged mice developed increased serum levels of OVA-specific IgE with significant airway eosinophilia and heightened responsiveness to methacholine when compared with nonsensitized animals. Administration of M. leprae hsp prevented both development of AHR as well as bronchoalveolar lavage fluid eosinophilia in a dose-dependent manner. Treatment with M. leprae hsp also resulted in suppression of IL-4 and IL-5 production in bronchoalveolar lavage fluid, while IL-10 and IFN-gamma production were increased. Furthermore, M. leprae hsp treatment significantly suppressed OVA-specific IgE production and goblet cell hyperplasia/mucin hyperproduction. In contrast, treatment with the other hsp failed to prevent changes in airway responsiveness, lung eosinophilia, or cytokine production. Depletion of gamma/delta T lymphocytes before sensitization and challenge abolished the effect of M. leprae hsp treatment on AHR. These results indicate selective and distinctive properties among the hsp, and that M. leprae hsp may have a potential therapeutic role in the treatment of allergic airway inflammation and altered airway function.
Assuntos
Proteínas de Bactérias/farmacologia , Hiper-Reatividade Brônquica/imunologia , Hiper-Reatividade Brônquica/microbiologia , Proteínas de Choque Térmico/farmacologia , Pulmão/patologia , Animais , Brônquios/imunologia , Brônquios/microbiologia , Brônquios/patologia , Hiper-Reatividade Brônquica/prevenção & controle , Líquido da Lavagem Broncoalveolar/imunologia , Líquido da Lavagem Broncoalveolar/microbiologia , Movimento Celular/imunologia , Citocinas/antagonistas & inibidores , Citocinas/biossíntese , Regulação para Baixo/imunologia , Epitopos/biossíntese , Feminino , Células Caliciformes/imunologia , Células Caliciformes/patologia , Hiperplasia , Imunoglobulina E/biossíntese , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Inflamação/imunologia , Inflamação/microbiologia , Interleucina-4/antagonistas & inibidores , Interleucina-4/biossíntese , Interleucina-5/antagonistas & inibidores , Interleucina-5/biossíntese , Pulmão/imunologia , Pulmão/microbiologia , Linfonodos/imunologia , Linfonodos/metabolismo , Depleção Linfocítica , Camundongos , Mucinas/antagonistas & inibidores , Mucinas/biossíntese , Mycobacterium leprae/fisiologia , Ovalbumina/farmacologia , Eosinofilia Pulmonar/microbiologia , Eosinofilia Pulmonar/prevenção & controle , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Mucosa Respiratória/imunologia , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , Subpopulações de Linfócitos T/imunologiaRESUMO
The presence of dormant tubercle bacilli presents a major problem for tuberculosis treatment. The culture supernatant of Mycobacterium tuberculosis was previously shown to resuscitate dormant bacilli in vitro. Here we report identification of active components as phospholipids and a tuberculosis protein Rv1174c. Remarkably, dormant bacilli from a one year old culture which failed to form any colonies could be resuscitated with peptides derived from Rv1174c and formed 10(5-7) colonies/ml. This finding represents the first unambiguous demonstration of resuscitation of dormant tubercle bacilli in vitro and may have implication for the study of mycobacterial dormancy and the design of novel strategies for improved treatment of tuberculosis.
Assuntos
Adaptação Biológica/efeitos dos fármacos , Proteínas de Bactérias/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Fosfolipídeos/farmacologia , Sequência de Aminoácidos , Anticorpos/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Divisão Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Dados de Sequência Molecular , Mycobacterium leprae/genética , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crescimento & desenvolvimento , Fragmentos de Peptídeos/antagonistas & inibidores , Análise de Sequência de Proteína , Homologia de Sequência do Ácido NucleicoRESUMO
Mycobacterium bovis BCG secretes two ATP-scavenging enzymes, nucleoside diphosphate kinase (Ndk) and ATPase, during growth in Middlebrook 7H9 medium. In synthetic Sauton medium without any protein supplements, there is less secretion of these two enzymes unless proteins such as bovine serum albumin (BSA), ovalbumin or extracts of macrophages are added to the medium. There is a gradient of activity among various proteins in triggering the induction of secretion of these two enzymes. Other mycobacteria, such as M. smegmatis, primarily secrete Ndk, while M. chelonae does not appear to secrete either of these two enzymes. Purification of the enzymes from the culture filtrate of 7H9-grown M. bovis BCG cells and determination of the N-terminal amino-acid sequence have demonstrated a high level of sequence identity of one of the ATPases with DnaK, a heat shock chaperone, of M. tuberculosis and M. leprae, while that of Ndk shows significant identity with the Ndk of Myxococcus xanthus. As both Ndk and ATPase use ATP as a substrate, the physiological significance of the secretion of these two ATP-utilizing enzymes was explored. External ATP is important in the activation of macrophage surface-associated P2Z receptors, whose activation has been postulated to allow phagosome-lysosome fusion and macrophage cell death. We demonstrate that the presence of the filtrate containing these enzymes prevents ATP-induced macrophage cell death, as measured by the release of an intracellular enzyme, lactate dehydrogenase. In vitro complexation studies with purified Ndk/ATPase and hyperproduced P2Z receptor protein will demonstrate whether these enzymes may be used by mycobacteria to sequester ATP from the macrophage P2Z receptors, thereby preventing phagosome-lysosome fusion or macrophage apoptotic death.
Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Fímbrias , Macrófagos/metabolismo , Mycobacterium bovis/enzimologia , Núcleosídeo-Difosfato Quinase/metabolismo , Receptores Purinérgicos P2/metabolismo , Adenosina Trifosfatases/isolamento & purificação , Animais , Proteínas de Bactérias/farmacologia , Morte Celular/fisiologia , Relação Dose-Resposta a Droga , GTP Fosfo-Hidrolases/metabolismo , L-Lactato Desidrogenase/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Núcleosídeo-Difosfato Quinase/isolamento & purificação , Receptores Purinérgicos P2X7 , Soroalbumina Bovina/farmacologia , Fatores de TempoRESUMO
We demonstrate that human T lymphocytes proliferate in vitro to highly purified human heat-shock protein 60 (Hu.hsp60). The response to this self Ag was confined to the CD45RA+ RO- T cell subset, with minimal responses by adult CD45RA- RO+ T cells. Experiments using keyhole limpet hemocyanin as a prototypic novel Ag, or tetanus toxoid as a recall Ag, were consistent with the notion that CD45RA+ RO- and CD45RA- RO+ T cell subsets can be designated as naive and memory cells, respectively; thus, responses to Hu.hsp60 were confined to the putative naive subset. In contrast, both CD45RA+ RO- and CD45RA- RO+ T cell populations proliferated to bacterial hsp60 from Mycobacterium leprae, Escherichia coli, or Chlamydia trachomatis. However, only CD45RA- RO+ (memory) T cells responded to a mycobacterial hsp60-derived peptide previously defined as a major bacteria-specific epitope. Experiments with cord blood T cells, which are CD45RA+ RO- and can be considered truly naive, showed that the peptide could elicit responses from naive T cells in vitro; cord blood cells also responded to Hu.hsp60. Since bacterial hsp60 Ags contain both conserved and nonconserved epitopes, we speculate that in vivo challenge with bacterial hsp60 will activate T cells capable of seeing either type of epitope, but only those that see nonconserved epitopes maintain the CD45RA- RO+ memory phenotype. However, T cells recognizing conserved epitopes, while not apparently being recruited to the memory pool, may nevertheless play a role in immunoregulation, particularly in the context of inflammation, when expression of Hu.hsp60 is increased.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Chaperonina 60/farmacologia , Antígenos Comuns de Leucócito/biossíntese , Subpopulações de Linfócitos T/imunologia , Adulto , Animais , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/farmacologia , Linfócitos T CD4-Positivos/metabolismo , Epitopos de Linfócito T/farmacologia , Haptenos/imunologia , Hemocianinas/imunologia , Humanos , Memória Imunológica , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Moluscos/imunologia , Mycobacterium bovis/imunologia , Isoformas de Proteínas/biossíntese , Subpopulações de Linfócitos T/metabolismoRESUMO
Sheep infected with maedi visna virus were tested for immune reactivity to recombinant HSP65 and tuberculin PPD from mycobacteria. The results showed that both naturally and experimentally infected animals had elevated IgM but not IgG or IgA antibodies to HSP65 from Mycobacterium leprae or M. bovis. In experimentally infected animals, the elevated IgM antibodies appeared in blood from about 3 to 4 weeks postinfection. Increased T cell proliferative responses to HSP65 and PPD were also found in both naturally and experimentally infected sheep. The T cell responses to HSP65 were substantially inhibited by antibodies to ovine major histocompatibility complex class II molecules, indicating that the responses were class II restricted. Increased expression of a putative HSP65 molecule was observed in synovial membranes from sheep infected with maedi visna virus and goats infected with the related, caprine arthritis encephalitis virus. The results thus show that lentivirus infection induces T and B cell anti-HSP65 immune responses and suggest that synovial inflammation may be due, at least in part, to T and B cell recognition of HSP65-like molecules expressed in joints.
Assuntos
Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Chaperoninas/imunologia , Chaperoninas/farmacologia , Proteínas de Choque Térmico/imunologia , Proteínas de Choque Térmico/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Pneumonia Intersticial Progressiva dos Ovinos/imunologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Vírus Visna-Maedi/imunologia , Animais , Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/farmacologia , Chaperonina 60 , Reações Cruzadas , Epitopos/imunologia , Inflamação/imunologia , Mycobacterium bovis/metabolismo , Mycobacterium leprae/metabolismo , Pneumonia Intersticial Progressiva dos Ovinos/sangue , Proteínas Recombinantes/sangue , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/farmacologia , Ovinos , Membrana Sinovial/imunologiaRESUMO
Bacterial heat shock proteins (hsp) have been shown to be important immunogens stimulating both T cells and B cells. However, little is known concerning the direct interactions between hsp and macrophages. In this study, we demonstrated that treatment of macrophage cultures with purified bacterial hsp, including Legionella pneumophila hsp60, Escherichia coli GroEL, Mycobacterium tuberculosis hsp70, Mycobacterium leprae hsp65, and Mycobacterium bovis BCG hsp65, increased the steady-state levels of cytokine mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor as well as supernatant IL-1 secretion. This effect was shown not to be due to contamination of the hsp preparations with bacterial lipopolysaccharide. However, not all hsp induced cytokines; M. tuberculosis hsp10 showed minimal activity in our study. These results suggest that bacterial hsp might modulate immunity by rapidly and directly increasing cytokine production in macrophages.
Assuntos
Proteínas de Bactérias/farmacologia , Citocinas/biossíntese , Proteínas de Choque Térmico/farmacologia , Macrófagos/metabolismo , Animais , Células Cultivadas , Citocinas/genética , Escherichia coli/química , Fator Estimulador de Colônias de Granulócitos e Macrófagos/biossíntese , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Interleucina-1/genética , Interleucina-1/metabolismo , Interleucinas/genética , Interleucinas/metabolismo , Legionella pneumophila/química , Macrófagos/efeitos dos fármacos , Camundongos , Mycobacterium/química , RNA Mensageiro/análise , Especificidade da Espécie , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genéticaRESUMO
Murine intraepithelial lymphocytes (IEL) respond poorly to T cell mitogens and to monoclonal antibody stimulation of T cell receptor (TCR)- and CD3- associated molecules. In contrast, we found that a soluble extract of Mycobacterium tuberculosis (Mtb), but not purified protein derivative of tuberculin, induced significant proliferative responses in IEL cultures. The active component was apparently a heat shock protein (HSP), since recombinant 71-kDa HSP from Mtb induced IEL to proliferate, while 65-kDa HSP from M. bovis and M. leprae did not. Both alpha/beta and gamma/delta TCR-enriched IEL gave proliferative responses to 71-kDa HSP. Further, culture supernatants from IEL stimulated with 71-kDa HSP contained elevated levels of interleukin-(IL)-3/granulocyte-macrophage colony-stimulating factor, interferon-gamma and IL-6, but not IL-2, IL-4, IL-5 or transforming growth factor-beta. Finally, several IEL T cell clones have been maintained for up to 6 weeks, when stimulated with 71-kDa HSP, IL-2 and feeder cells. Our results show that the 71-kDa HSP of Mtb induces IEL T cells to divide and to secrete cytokines and this may offer a model for cloning and study of IEL T cells in vitro.
Assuntos
Proteínas de Bactérias/farmacologia , Citocinas/biossíntese , Proteínas de Choque Térmico/farmacologia , Intestinos/imunologia , Ativação Linfocitária/efeitos dos fármacos , Mycobacterium tuberculosis/imunologia , Animais , Células Cultivadas , Interleucina-2/farmacologia , Intestinos/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BLRESUMO
In vitro and in vivo responses to the 18-kDa protein of Mycobacterium leprae have been analysed in different strains of mice. Lymphocytes from BALB/cJ (H-2d), BALB.B (H-2b), B10.BR (H-2k), and B10.M (H-2f) mice primed with 18-kDa protein yielded high T cell proliferative responses, while those from C57BL/10J (H-2b) mice yielded lower responses. Both H-2 and non-H-2 genes contributed to the magnitude of responsiveness. F1 mice from high and low responder strains showed high responsiveness to the 18-kDa protein. Supernatants from lymph node cell cultures prepared from 18-kDa protein-immunised BALB/cJ, B10.BR, and C57BL/10J mice contained IL-2 but no IL-4, indicating that activated T cells from both high and low responder mice were of a TH1 phenotype. Cell cultures from low responder C57BL/10J mice produced less IL-2 than those from high responders. The low responsiveness to the 18-kDa protein in proliferative assays might be due to a low frequency of antigen-specific T cells in the C57BL/10J mouse strain. BALB/cJ, C57BL/10J, and F1 (BALB/cJ x B10.BR) mouse strains were tested for in vivo DTH reactions to the 18-kDa protein. All strains, including C57BL/10J, were high DTH responders. Although DTH effector cells and 18-kDa protein-specific proliferative T cells belong to the TH1 subset, our data comparing high and low responder status indicate that distinct TH1 subpopulations are stimulated in response to the 18-kDa protein of M. leprae.
Assuntos
Proteínas de Bactérias/farmacologia , Hipersensibilidade Tardia/genética , Ativação Linfocitária/genética , Mycobacterium leprae , Subpopulações de Linfócitos T/imunologia , Animais , Proteínas de Bactérias/administração & dosagem , Divisão Celular , Células Cultivadas/efeitos dos fármacos , Hipersensibilidade Tardia/imunologia , Interleucina-2/análise , Interleucina-4/análise , Camundongos , Camundongos Endogâmicos , Mycobacterium leprae/química , Mycobacterium tuberculosis/químicaRESUMO
Macrophages from peripheral blood of leprosy patients, both multi-bacillary and paucibacillary are unable to kill phagocytosed Mycobacterium leprae due to their inability to produce superoxide (O2-) and hydroxyl radicals (OH.). The macrophages from healthy individuals are able to kill M. leprae along with release of O2- and OH. radicals. The deficiency in the macrophages of both types of leprosy patients is removed by activation of these cells when exposed to a culture supernatant obtained after stimulation of peripheral blood mononuclear cells from the same patients with delipidified cell components of M. leprae which are most likely cell wall proteins. The activation of macrophages also leads to recognition of whole live M. leprae as an antigen by cells from lepromatous patients. This activation of the phagocytes by delipidified cell components is blocked by cyclosporin A, indicating the possible role of several steps involved in immune activation of cells. The observations thus indicate the significant ability of delipidified cell components to eliminate the deficiencies in the macrophages from leprosy patients and restore them to behave like the cells from healthy individuals. Considering all these, it is suggested that delipidified cell components could be potential modulators, and are probably capable of functioning as a vaccine for leprosy.