RESUMO
The helminth Schistosoma mansoni is one of main causes of human schistosomiasis, a health and economic concern in some of the world's poorest countries. Current treatment regimens can lead to serious side effects and are not suitable for breastfeeding mothers. As such, efforts have been undertaken to develop a vaccine to prevent infection. Of these, Sm29 is a promising candidate that has been associated with resistance to infection/reinfection in humans and mice. Its ability to induce resistance to reinfection has also been recently demonstrated using a vaccine formulation containing Freund's adjuvant. However, Freund's adjuvant is unsuitable for use in human vaccines. We therefore evaluated the ability of Sm29 to induce protection against S. mansoni reinfection when formulated with either alum or MPLA as an adjuvant, both approved for human use. Our data demonstrate that, in contrast to Sm29 with MPLA, Sm29 with alum reduced parasite burden after reinfection compared to a control. We next investigated whether the immune response was involved in creating the differences between the protective (Sm29Alum) and non-protective (Sm29MPLA) vaccine formulations. We observed that both formulations induced a similar mixed-profile immune response, however, the Sm29 with alum formulation raised the levels of antibodies against Sm29. This suggests that there is an association between a reduction in worm burden and parasite-specific antibodies. In summary, our data show that Sm29 with an alum adjuvant can successfully protect against S. mansoni reinfection in mice, indicating a potentially effective vaccine formulation that could be applied in humans.
Assuntos
Antígenos de Helmintos/imunologia , Imunidade Humoral , Schistosoma mansoni/fisiologia , Esquistossomose mansoni/imunologia , Vacinas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Adjuvantes Imunológicos/química , Compostos de Alúmen/administração & dosagem , Compostos de Alúmen/química , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Helmintos/química , Resistência à Doença , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , VacinaçãoRESUMO
The immune response induced by Schistosma mansoni antigens is able to prevent immune-mediated diseases. Conversely, the inflammatory response in cutaneous leishmaniasis (CL), although responsible for controlling the infection, is also associated with the pathogenesis of disease. The aim of this study was to evaluate the potential of the S. mansoni Sm29 antigen to change certain aspects of the profiles of monocyte derived dendritic cells (MoDCs) and lymphocytes from subjects with CL in vitro. Expression of surface molecules and intracellular cytokines in the MoDCs and lymphocytes as well as the proliferation of Leishmania braziliensis were evaluated by flow cytometry. Levels of cytokines were evaluated in culture supernatants by ELISA. It was observed that stimulation by rSm29 increased the frequency of expression of CD83, CD80, CD86, and IL-10R in MoDCs compared to non-stimulated cultures. Additionally rSm29 decreased the frequency CD4+ and CD8+ T cells expressing CD28 and increased the frequency of CD4+CD25hi and CD4+CTLA-4+ T lymphocytes. Addition of rSm29 to cultures increased IL-10 levels and decreased levels of IL-12p40 and IFN-γ, while not altering TNF levels compared to non-stimulated cultures. This study showed that rSm29 induced a regulatory profile in MoDCs and lymphocytes and thereby regulated the exaggerated inflammation observed in CL. Considering that there are few therapeutic options for leishmaniasis, the use of rSm29 may be an alternative to current treatment and may be an important strategy to reduce the healing time of lesions in patients with CL.
Assuntos
Antígenos de Helmintos/imunologia , Células Dendríticas/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/microbiologia , Linfócitos/imunologia , Schistosoma mansoni/imunologia , Animais , Células Cultivadas , Técnicas de Cocultura , Citocinas/metabolismo , Células Dendríticas/metabolismo , Suscetibilidade a Doenças , Feminino , Humanos , Leishmaniose Cutânea/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Ativação Linfocitária/imunologia , Linfócitos/metabolismo , Masculino , Fenótipo , Proteínas Recombinantes/imunologiaRESUMO
Asthma is a chronic disease characterized by airway inflammation, obstruction and hyperresponsiveness. Severe asthma affects a small proportion of subjects but results in most of the morbidity, costs and mortality associated with the disease. Studies have suggested that Schistosoma mansoni infection reduces the severity of asthma and prevent atopy. OBJECTIVE: We evaluated the ability of S. mansoni antigens, Sm29 and Sm29TSP-2 to modulate lymphocyte activation status in response to the allergen of the mite Dermatophagoides pteronyssinus (Der p1) in cell cultures of individuals with asthma. METHODS: Thirty four patients were enrolled in this study: seventeen patients with severe asthma (SA group), seventeen patients with mild asthma (MA group) and six controls with no asthma. Peripheral blood mononuclear cells (PBMC) were obtained and stimulated with Sm29 and Sm29TSP-2 in the presence or absence of Der p1. The expression of surface markers and cytokines on lymphocytes was evaluated by flow cytometry and the levels of IL-10 in the culture supernatant were determined by ELISA. RESULTS: The addition of Sm29 and Sm29TSP-2 antigens to PBMC cultures from both groups of subjects with asthma stimulated with Der p1 reduced the frequency of CD4+CD25low cells whereas and increased frequency of CD4+CD25high population was observed compared to unstimulated cultures. Moreover, cultures stimulated with Sm29TSP-2 showed a reduction in the frequency of T cells expressing CD69, IFN-γ, TNF and TGF-ß in the MA group and an increase in the frequency of CD4+TSLPR+ T cells in the SA group. The addition of Sm29 to the cultures reduced the frequency of CD4+CD69+ and CD4+IL-5+ T cells in all asthmatic groups, and reduced the frequency of CD4+ T cells expressing IL-13 in the MA group. The cultures stimulated with Sm29 and Sm29TSP-2 showed an increase in the level of IL-10 in the supernatants. CONCLUSION: These results suggest that the addition of Sm29 and Sm29TSP-2 to the cells cultures from subjects with asthma reduced cell activation markers and altered the cytokine production pattern in a way that can potentialy control the inflammatory response associated with asthma.
Assuntos
Antígenos de Helmintos/sangue , Asma/sangue , Citocinas/sangue , Leucócitos Mononucleares/parasitologia , Schistosoma mansoni/imunologia , Adulto , Animais , Asma/parasitologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/parasitologia , Estudos de Casos e Controles , Feminino , Humanos , Interleucina-10/sangue , Interleucina-13/sangue , Interleucina-5/sangue , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Fator de Crescimento Transformador beta/metabolismoRESUMO
Schistosoma mansoni is a blood fluke parasite responsible for schistosomiasis. The best long-term strategy to control schistosomiasis is through immunization combined with drug treatment. In this study, we cloned, expressed and purified SmTSP-2 fused to the N- and C-terminal halves of Sm29 and tested these chimeras as vaccine candidates using an adjuvant approved to be used in humans. The results demonstrated that vaccination with SmTSP-2 fused to N- or C-terminus of Sm29-induced reduction in worm burden and liver pathology when compared to control animals. Additionally, we detected high levels of mouse-specific IgG, IgG1 and IgG2a against both chimeras and significant amounts of IFN-γ and TNF-α and no IL-4. Finally, studies with sera from patients resistant to infection and living in schistosomiasis endemic areas revealed high levels of specific IgG to both chimeras when compared to healthy individuals. In conclusion, SmTSP-2/Sm29 chimeras tested here induced partial protection against infection and might be a potential vaccine candidate.
Assuntos
Antígenos de Bactérias/imunologia , Antígenos de Helmintos/imunologia , Proteínas de Bactérias/imunologia , Proteínas de Helminto/imunologia , Glicoproteínas de Membrana/imunologia , Schistosoma mansoni , Esquistossomose mansoni/imunologia , Esquistossomose mansoni/prevenção & controle , Tetraspaninas/imunologia , Vacinas/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Anti-Helmínticos/sangue , Antígenos de Bactérias/administração & dosagem , Antígenos de Helmintos/administração & dosagem , Proteínas de Bactérias/administração & dosagem , Ilhas de CpG , Citocinas/sangue , Feminino , Proteínas de Helminto/administração & dosagem , Humanos , Imunoglobulina G/sangue , Fígado/patologia , Glicoproteínas de Membrana/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Oligodesoxirribonucleotídeos/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/imunologia , Tetraspaninas/administração & dosagem , Vacinas/administração & dosagemRESUMO
Schistosoma mansoni infection or associated products are able to down-modulate the type 1 CD4+ T cell inflammatory response characteristic of autoimmune diseases. In this study, we evaluated how S. mansoni antigens altered the immune response that was induced by the soluble Leishmania antigen (SLA) from cutaneous leishmaniasis (CL) patients. Cytokines were measured from the supernatants of peripheral blood mononuclear cell cultures stimulated with SLA. This was performed using the sandwich enzyme linked immunosorbent assay technique in the presence or absence of S. mansoni recombinant antigens Sm29, SmTSP-2 and PIII. The addition of S. mansoni antigens to the cultures resulted in the reduction of interferon gamma (IFN-γ) levels in 37-50 percent of patients. Although to a lesser extent, the antigens were also able to decrease the production of tumour necrosis factor-alpha (TNF-α). We compared patients that either had or did not have reduction in IFN-γ and TNF-α production in cultures stimulated with SLA in the presence of S. mansoni antigens. We found that there was no significant difference in the levels of interleukin (IL)-10 and IL-5 in response to S. mansoni antigens between the groups. The antigens used in this study down-modulated the in vitro proinflammatory response induced by SLA in a group of CL patients through a currently undefined mechanism.
Assuntos
Adolescente , Adulto , Animais , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Antígenos de Protozoários/farmacologia , Citocinas/biossíntese , Leishmaniose Cutânea/imunologia , Leucócitos Mononucleares/imunologia , Schistosoma mansoni/imunologia , Antígenos de Protozoários/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Interferon gama/biossíntese , /biossíntese , /biossíntese , Leishmaniose Cutânea/sangue , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Progress in schistosome genome research has enabled investigators to move rapidly from genome sequences to vaccine development. Proteins bound to the surface of parasites are potential vaccine candidates, or they can be used for diagnosis. We analyzed 4342 proteins deduced from the Schistosoma mansoni transcriptome with bioinformatic computer programs. Thirty-four proteins had membrane-bound motifs. Within this group, we selected the Sm29 protein to be further characterized by in silico analysis. Sm29 was found to have a signal peptide made up of 26 amino acids, with a cleavage site between Ser26 and Val27. The glycosylation site search revealed three threonines (39, 132 and 133) with high probability of O-glycosylation and two asparagines (58 and 115) with high probability of N-glycosylation. Only one transmembrane helix was found in the C-terminal region of the protein from Leu169 to Lis191. The search for similarities and conserved motifs show that Sm29 is a protein with high identity to proteins present in S. japonicum (53, 52, 49, and 37% of identity) and it possesses disulfide-rich conserved domains. Apparently, Sm29 is a membrane bound protein, and it may be an important molecule in host-parasite interactions.