RESUMO
Infection with Streptococcus pyogenes (S. pyogenes) can result in several diseases, particularly in children. S. pyogenes M protein is the major virulence factor, and certain regions of its N-terminus can trigger autoimmune sequelae such as rheumatic fever in susceptible individuals with untreated group A streptococcal pharyngitis. In a previous study, we utilized a large panel of human peripheral blood cells to define the C-terminal protective epitope StreptInCor (medical identity), which does not induce autoimmune reactions. We recently confirmed the results in HLA-transgenic mice. In the present study, we extended the experimental assays to outbred animals (Swiss mice). Herein, we demonstrate high titers of StreptInCor-specific antibodies, as well as appropriate T-cell immune responses. No cross-reaction to cardiac myosin was detected. Additionally, immunized Swiss mice exhibited 87% survival one month after challenge with S. pyogenes. In conclusion, the data presented herein reinforce previous results in humans and animals and further emphasize that StreptInCor could be an effective and safe vaccine for the prevention of S. pyogenes infections.
Assuntos
Vacinas Bacterianas/imunologia , Cruzamento , Epitopos/imunologia , Infecções Estreptocócicas/prevenção & controle , Streptococcus pyogenes/imunologia , Streptococcus pyogenes/fisiologia , Vacinas de Subunidades Antigênicas/imunologia , Sequência de Aminoácidos , Animais , Especificidade de Anticorpos , Aderência Bacteriana/imunologia , Vacinas Bacterianas/química , Linhagem Celular , Proliferação de Células , Feminino , Humanos , Imunização , Imunoglobulina G/imunologia , Camundongos , Dados de Sequência Molecular , Polimorfismo Genético , Especificidade da Espécie , Baço/citologia , Infecções Estreptocócicas/sangue , Infecções Estreptocócicas/genética , Vacinas de Subunidades Antigênicas/químicaRESUMO
Rheumatic fever (RF) is an autoimmune disease triggered by Streptococcus pyogenes infection frequently observed in infants from developing countries. Rheumatic heart disease (RHD), the major sequel of RF, leads to chronic inflammation of the myocardium and valvular tissue. T cells are the main population infiltrating cardiac lesions; however, the chemokines that orchestrate their recruitment are not clearly defined. Here, we investigated the expression of chemokines and chemokine receptors in cardiac tissue biopsies obtained from chronic RHD patients. Our results showed that CCL3/MIP1α gene expression was upregulated in myocardium while CCL1/I-309 and CXCL9/Mig were highly expressed in valvular tissue. Auto-reactive T cells that infiltrate valvular lesions presented a memory phenotype (CD4(+)CD45RO(+)) and migrate mainly toward CXCL9/Mig gradient. Collectively, our results show that a diverse milieu of chemokines is expressed in myocardium and valvular tissue lesions and emphasize the role of CXCL9/Mig in mediating T cell recruitment to the site of inflammation in the heart.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Quimiocina CXCL9/metabolismo , Valvas Cardíacas/imunologia , Miocárdio/imunologia , Cardiopatia Reumática/imunologia , Adolescente , Adulto , Movimento Celular/imunologia , Quimiocina CCL1/biossíntese , Quimiocina CCL1/imunologia , Quimiocina CCL3/biossíntese , Quimiocina CCL3/imunologia , Quimiocina CXCL9/biossíntese , Criança , Pré-Escolar , Feminino , Fibrose , Valvas Cardíacas/metabolismo , Humanos , Memória Imunológica/imunologia , Masculino , Pessoa de Meia-Idade , Miocárdio/metabolismo , Neovascularização Patológica/imunologia , Febre Reumática/imunologia , Febre Reumática/microbiologia , Streptococcus pyogenes , Adulto JovemRESUMO
Streptococcus pyogenes infections remain a health problem in several countries because of post-streptococcal sequelae, such as rheumatic fever and rheumatic heart disease. We developed a vaccine epitope (StreptInCor) composed of 55 amino acid residues of the C-terminal portion of the M protein that encompasses both T and B cell protective epitopes. Recently, by using human blood samples, we showed that the StreptInCor epitope is able to bind to different HLA class II molecules and that it could be considered a universal vaccine epitope. In the present work, we evaluated the immune response of HLA class II transgenic mice against aluminum hydroxide-absorbed StreptInCor. After a period of one year, several organs were analyzed histologically to verify the safety of the candidate vaccine epitope. Our results showed that StreptInCor is able to induce robust and safe and long lasting immune response without deleterious reactions in several organs. In conclusion, the results presented here indicate that StreptInCor could be considered a safe vaccine against severe streptococcus-induced diseases.
Assuntos
Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Transporte/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Vacinas Estreptocócicas/efeitos adversos , Vacinas Estreptocócicas/imunologia , Streptococcus pyogenes/imunologia , Adjuvantes Imunológicos/administração & dosagem , Compostos de Alúmen/administração & dosagem , Estruturas Animais/patologia , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Transporte/genética , Epitopos/genética , Epitopos/imunologia , Feminino , Antígenos de Histocompatibilidade Classe II/genética , Histocitoquímica , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Masculino , Camundongos , Camundongos Transgênicos , Microscopia , Vacinas Estreptocócicas/administração & dosagem , Streptococcus pyogenes/genéticaRESUMO
Rheumatic fever (RF) is a sequel of group A streptococcal throat infection and occurs in untreated susceptible children. Rheumatic heart disease (RHD), the major sequel of RF, occurs in 30%-45% of RF patients. RF is still considered endemic in some regions of Brazil and is responsible for approximately 90% of early childhood valvular surgery in the country. In this study, we present a 15-year clinical follow-up of 25 children who underwent surgical valvular repair. Histopathological and immunological features of heart tissue lesions of RHD patients were also evaluated. The patients presented severe forms of RHD with congestive symptoms at a very young age. Many of them had surgery at the acute phase of RF. Histological analysis showed the presence of dense valvular inflammatory infiltrates and Aschoff nodules in the myocardium of 21% of acute RHD patients. Infiltrating T-cells were mainly CD4+ in heart tissue biopsies of patients with rheumatic activity. In addition, CD4+ and CD8+ infiltrating T-cell clones recognized streptococcal M peptides and cardiac tissue proteins. These findings may open the possibilities of new ways of immunotherapy. In addition, we demonstrated that the surgical procedure during acute phase of the disease improved the quality of life of young RHD patients.
Assuntos
Cardiopatia Reumática/imunologia , Cardiopatia Reumática/patologia , Adolescente , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Biópsia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Proteínas de Transporte/imunologia , Criança , Células Clonais/imunologia , Feminino , Seguimentos , Doenças das Valvas Cardíacas/patologia , Doenças das Valvas Cardíacas/cirurgia , Humanos , Imuno-Histoquímica , Masculino , Miocárdio/patologia , Qualidade de VidaRESUMO
Heart lesions of rheumatic heart disease (RHD) patients contain T-cell clones that recognize heart proteins and streptococcal M peptides. To functionally characterize heart-infiltrating T lymphocytes, we evaluated their cytokine profile, both directly in situ and in T-cell lines derived from the heart (HIL). Interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-10 expressions were characterized in 20 heart tissue infiltrates from 14 RHD patients by immunohistochemistry. IFN-gamma-, TNF-alpha-, and IL-10-positive cells were consistently predominant, whereas IL-4 was scarce in the valves. In agreement with these data, the in vitro experiments, in which 13 HILs derived from heart samples of eight patients were stimulated with M5 protein and the immunodominant M5 (81-96) peptide, IL-4 was detected in HIL derived from the atrium (three of six) but not from the valve (zero of seven). IFN-gamma and IL-10 production were detected in culture supernatants in 11 of 13 and 6 of 12 HILs, respectively. The predominant IFN-gamma and TNF-alpha expression in the heart suggests that Th1-type cytokines could mediate RHD. Unlike in reversible myocardium inflammation, the significantly lower IL-4 expression in the valvular tissue (P = 0.02) may contribute to the progression of the RHD leading to permanent valvular damage (relative risk, 4.3; odds ratio, 15.8). The lack of IL-4 in vitro production by valve-derived HIL also emphasizes the more severe tissue destruction in valves observed in RHD.