Recombinant BCG expressing the LTAK63 adjuvant increased memory T cells and induced long-lasting protection against Mycobacterium tuberculosis challenge in mice

Vaccine-induced protection against Mycobacterium tuberculosis (Mtb) is usually ascribed to the induction of Th1, Th17, and CD8+ T cells. However, protective immune responses should also involve other immune cell subsets, such as memory T cells. We have previously shown improved protection against Mtb challenge using the rBCG-LTAK63 vaccine (a recombinant BCG strain expressing the LTAK63 adjuvant, a genetically detoxified derivative of the A subunit from E. coli heat-labile toxin). Here we show that mice immunized with rBCG-LTAK63 exhibit a long-term (at least until 6 months) polyfunctional Th1/Th17 response in the draining lymph nodes and in the lungs. This response was accompanied by the increased presence of a diverse set of memory T cells, including central memory, effector memory and tissue-resident memory T cells. After the challenge, the T cell phenotype in the lymph nodes and lungs were characterized by a decrease in central memory T cells, and an increase in effector memory T cells and effector T cells. More importantly, when challenged 6 months after the immunization, this group demonstrated increased protection in comparison to BCG. In conclusion, this work provides experimental evidence in mice that the rBCG-LTAK63 vaccine induces a persistent increase in memory and effector T cell numbers until at least 6 months after immunization, which correlates with increased protection against Mtb. This improved immune response may contribute to enhance the long-term protection

Non-disulfide-Bridge peptide 5.5 from the Scorpion Hadrurus gertschi Inhibits the growth of mycobacterium abscessus subsp. massiliense

Multi-drug resistant microorganisms have been a growing concern during the last decades due to their contribution in mortality rates worldwide. Antimicrobial peptides (AMPs) are broad spectrum antimicrobial agents that display potent microbicidal activity against a wide range of microorganisms. AMPs generally have a rapid mode of action that reduces the risk of resistance developing among pathogens. In this study, an AMP derived from scorpion venom, NDBP-5.5, was evaluated against Mycobacterium abscessus subsp. massiliense, a rapidly growing and emerging pathogen associated with healthcare infections. The minimal bactericidal concentration of NDBP-5.5, AMP quantity necessary to stop bacteria visible growth, against M. abscessus subsp. massiliense was 200 μM, a concentration that did not induce hemolysis of human red blood cells. The therapeutic index was 3.05 indicating a drug with low toxicity and therefore good clinical potential. Treatment of infected macrophages with NDBP-5.5 or clarithromycin presented similar results, reducing the bacterial load. M. abscessus subsp. massiliense-infected animals showed a decrease in the bacterial load of up to 70% when treated with NDBP-5.5. These results revealed the effective microbicidal activity of NDBP-5.5 against Mycobacterium, indicating its potential as an antimycobacterial agent

Uso de lipossomas microestruturados na formulação de vacinas de subunidade protéica HspX para tuberculose

Submitted by Erika Demachki ([email protected]) on 2015-10-21T17:09:00Z No. of bitstreams: 2 Dissertação - Monalisa Martins Trentini - 2014.pdf: 3160453 bytes, checksum: bcd4f593c1bbefa247afd83aa66ef627 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Approved for entry into archive by Erika Demachki ([email protected]) on 2015-10-21T17:16:56Z (GMT) No. of bitstreams: 2 Dissertação - Monalisa Martins Trentini - 2014.pdf: 3160453 bytes, checksum: bcd4f593c1bbefa247afd83aa66ef627 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Made available in DSpace on 2015-10-21T17:16:56Z (GMT). No. of bitstreams: 2 Dissertação - Monalisa Martins Trentini - 2014.pdf: 3160453 bytes, checksum: bcd4f593c1bbefa247afd83aa66ef627 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-27Tuberculosis is a disease that affects thousands of people in the World. Although Brazil Health Program had achieved the goal of reducing to 50% the rate of death induced by Tuberculosis, this disease continues to be the second cause of death by infectious disease. One of the main problems to control the disease is the low efficacy of BCG vaccine in protecting young adults. The development of new vaccines that induces long lasting immune response or that stimulate the immunity induced by BCG may improve the control of TB spreading. This study evaluated the use of microstructured liposomes containing HspX with or without MPL or CpG DNA adjuvants as vaccine for tuberculosis. The HspX specific humoral and cellular immune responses were compared between the different vaccine formulations. All vaccines containing liposome microparticules and HspX were immunogenic and antigenic. Vaccines formulated with CpG DNA and HspX induced the strongest humoral and cellular immune responses, mainly by generating IFN- and TNF-by both CD4 and CD8 T cells. HspX and MPL mainly induced CD8 T cell activation and humoral specific responses. After protection efficacy evaluation against Mycobacterium tuberculosis challenge, the vaccine formulation that reduced both lung inflammatory lesions and the bacterial load was the microstructured liposome containing HspX and CPG DNA. These results show for the first time the use of microstructured liposome as adjuvant and delivery system in HspX vaccine formulation for tuberculosis.A tuberculose é uma doença que acomete milhões de indivíduos no mundo. No Brasil esta doença é a segunda causa de morte por doença infectocontagiosa, embora o País tenha reduzido a metade o numero de mortes por tuberculose. Um dos principais problemas para o controle desta doença é a baixa eficácia da vacina BCG em proteger adultos. O desenvolvimento de novas vacinas que induzam uma resposta imune eficaz e duradoura, ou que estimulem a BCG a aumentar a imunidade já existente é de grande valia. O objetivo desta dissertação foi avaliar e comparar se lipossomas microestruturados contendo HspX em diferentes formulações vacinais, associados ou não a adjuvantes conhecidos: CpG DNA ou MPL poderiam influenciar na resposta imune humoral e celular de camundongos contra o Mycobacterium tuberculosis. Nossos resultados mostram que lipossomas microestruturados contendo HspX foram imunogênicos e antigênicos. As formulações vacinais contendo o adjuvante CpG DNA foram as principais indutoras de resposta humoral e celular específica, principalmente com produção de IFN- e TNF- tanto por linfócitos T CD4+ quanto CD8+. Formulações vacinais contendo HspX e MPL induziram resposta imune humoral e ativaram principalmente linfócitos T CD8. A formulação vacinal que melhor reduziu as lesões pulmonares provocadas pelo Mycobacterium tuberculosis, assim como a carga bacilar foi a composta por lipossomas microestruturados contendo HspX e CpG DNA. Estes resultados demonstram pela primeira vez o uso de lipossomas microestruturados em formulações de vacinas com o antígeno HspX para a tuberculose

Robust Immune Response and Protection against Lethal Pneumococcal Challenge with a Recombinant BCG-PspA-PdT Prime/Boost Scheme Administered to Neonatal Mice

Pneumococcal diseases are an important public health problem, with high mortality rates in young children. Although conjugated pneumococcal vaccines offer high protection against invasive pneumococcal diseases, this is restricted to vaccine serotypes, leading to serotype replacement. Furthermore, the current vaccines do not protect neonates. Therefore, several protein-based pneumococcal vaccines have been studied over the last few decades. Our group established a recombinant BCG expressing rPspA-PdT as a prime/rPspA-PdT boost strategy, which protected adult mice against lethal intranasal pneumococcal challenge. Here, we immunized groups of neonate C57/Bl6 mice (6–10) (at 5 days) with rBCG PspA-PdT and a boost with rPspA-PdT (at 12 days). Controls were saline or each antigen alone. The prime/boost strategy promoted an IgG1 to IgG2c isotype shift compared to protein alone. Furthermore, there was an increase in specific memory cells (T and B lymphocytes) and higher cytokine production (IFN-γ, IL-17, TNF-α, IL-10, and IL-6). Immunization with rBCG PspA-PdT/rPspA-PdT showed 100% protection against pulmonary challenge with the WU2 pneumococcal strain; two doses of rPspA-PdT showed non-significant protection in the neonates. These results demonstrate that a prime/boost strategy using rBCG PspA-PdT/rPspA-PdT is effective in protecting neonates against lethal pneumococcal infection via the induction of strong antibody and cytokine responses

Different phenotypes of CD8+ T cells associated with bacterial load in active tuberculosis

AbstractTuberculosis is an infectious disease that affects millions of people worldwide with an annual mortality rate of 1.3 million. The mechanisms contributing to the loss of balance of immune responses and progression to active tuberculosis disease are unknown. Although CD4+ and CD8+ T cells and the cytokines they produce are crucial for protection against tuberculosis they have different roles in tuberculosis immunology. The function of CD4+ T cells has been extensively studied; however, less is known about the phenotype and function of CD8+ T cells. This study evaluated the specific expression of IFN-γ, IL-17, IL-10, and TGF-β and ex vivo expression of perforin and granzyme-B by CD8+ T cells from active tuberculosis individuals compared with latent infected individuals and non-latent infected individuals. Tuberculosis responses were correlated with the baciloscopy score. We observed that the presence of IL-10 and TGF-β expression and down-expression of granzyme-B in CD8+ T cells correlated with increased sputum bacillary load in active tuberculosis individuals. These findings provide new insights into the role of CD8+ T cells in Mycobacterium tuberculosis disease