The Role of M. leprae

Experimental autoimmune uveitis (EAU) is a well established model for immune-mediated organ-specific disease. Our group has recently shown that the M. leprae Hsp65 aggravated the uveitis in mice; in the present study, we evaluated the action of M. leprae  K409A mutant protein and the synthetic peptides Leader pep and K409A pep (covering amino acids residues 352–371 of WT and K409A proteins of M. leprae Hsp65, resp.) on the pathogenesis of EAU. Mice received the 161–180 IRBP peptide and B. pertussis toxin followed by the intraperitoneal inoculation of K409A protein or the Leader pep or K409A pep. The Leader pep aggravated the disease, but mice receiving the K409A pep did not develop the disease and presented an increase in IL-10 levels by spleen cells and a decrease in the percentage of CD4+ IFN-γ+ T cells. Moreover, animals receiving the Leader pep presented the highest scores of the disease associated with increase percentage of CD4+ IFN-γ+ T cells. These results would contribute to understanding of the pathogenesis of EAU and support the concept that immune responses to Hsp are of potential importance in exacerbating, perpetuating, or even controlling organ-restricted autoimmune diseases, and it is discussed the irreversibility of autoimmune syndromes

Métodos alternativos para a detecção de pirogênios em produtos e ambientes sujeitos a Vigilância Sanitária: avanços e perspectivas no Brasil a partir do reconhecimento internacional do Teste de Ativação de Monócitos

Introduction: The detection of pyrogens is essential for the quality control of injectable products. The Rabbit Pyrogen Test remains widely used, despite the existence of alternative methods such as the Monocyte Activation Test (MAT). Objective: To review the use of alternative methods for pyrogen testing, pointing out advances and perspectives from the recognition of MAT by the European pharmacopoeia and its acceptance for regulatory purposes in Brazil. Method: A search was performed on the PubMed and BVS databases, with further classification, categorization by topic and critical analysis of the results. Results: Twenty-four papers were identified, addressing topics such as applications of MAT, its validation and comparisons with in vivo tests. MAT presented better results when compared to other tests, both in the evaluation of biological products and in the detection of non-endotoxin pyrogens. Limitations to diffusion include difficulties in obtaining whole human blood as a source of monocytes, for which several alternatives have been proposed. Conclusions: MAT is a promising method, with application in safety evaluation of new technologies. Its application in Brazil depends on a national implementation policy, which might include greater integration between BraCVAM, Concea and RENAMA in search for its recognition for regulatory purposes.Introdução: A detecção de pirogênios é imprescindível no controle da qualidade de produtos injetáveis. O Teste de Pirogênio em coelhos ainda tem larga aplicação, apesar da existência de métodos alternativos como o Teste de Ativação de Monócitos (MAT). Objetivo: Revisar o uso dos métodos alternativos no teste de pirogênio, apontando avanços e perspectivas a partir do reconhecimento do MAT pela Farmacopeia Europeia e sua aceitação para fins regulatórios no Brasil. Método: Uma busca foi realizada nas bases PubMed e BVS, com posterior classificação, categorização por assuntos e análise crítica dos resultados. Resultados: Foram identificados 24 trabalhos, abordando temas como as aplicações do MAT, sua validação e comparação com testes in vivo. O MAT apresentou melhores resultados quando comparado a outros testes, tanto na avaliação de produtos biológicos como na detecção de pirogênios não-endotoxinas. Limitações para sua difusão incluem a dificuldade de obtenção de sangue total humano como fonte de monócitos, para o qual diversas alternativas têm sido propostas. Conclusões: O MAT se mostra um método promissor, com aplicação na avaliação da segurança de novas tecnologias. Sua aplicação no Brasil depende de uma política nacional de implantação, que inclua maior Integração entre BraCVAM, Concea e RENAMA na busca por seu reconhecimento para fins regulatórios

Characterization of primary specicity of the Mycobacterium leprae rhsp65 and study of relationship of this catalytic activity with its immunogenicity

Neste trabalho, o possivel envolvimento da atividade proteolitica da hsp65 chaperonina 2 (cpn2) de M. leprae na apresentacao de epitopos MHC classe 1 esta sendo sugerido. O estudo da especificidade primaria da hsp65 recombinante cpn 2 de Mycobacterium leprae frente a substratos peptidicos fluorescentes, mostrou especificidade por residuos basicos em posicao P,, em adicao a atividade tripsina-simile, fato que ja foi relatado pelo nosso grupo (Portaro e cols, 2002). Observou-se hidrolise de substratos de tamanho restrito, entre 7 e 13 residuos de aminoacidos e, em menor proporcao, clivagem da ligacao peptidica no substrato analogo ao receptor de trombina PARI envolvendo aminoacido hidrofobico (Phe) em PI. Durante o estudo da caracterizacao de sua atividade proteolitica, verificamos, pela primeira vez, que apresenta atividade ATPasica (Km 95 p.M e kcat = 2,6 min -1) e que sua atividade enzimatica e influenciada por nucleotideos e cations monovalentes e bivalentes. Esse trabalho, ainda, corelaciona as sequencias de aminoacidos, focalizando epitopos MHC classe 1, e as atividades adjuvantes e cataliticas de hsps65. As possiveis implicacoes fisiopatologicas da atividade proteolitica da hsp65 de M. leprae estao agora sob ampla investigacao em nosso laboratorioBV UNIFESP: Teses e dissertaçõe

Sensing CA 15-3 in point-of-care by electropolymerizing <i>O</i>-phenylenediamine (oPDA) on Au-screen printed electrodes

<div><p>This work presents an alternative device for cancer screening in liquid biopsies. It combines a biomimetic film (i) with electrochemical detection (ii). The biomimetic film (i) was obtained by electro-polymerizing amine-substituted benzene rings around a CA 15–3 target. This protein target was previously adsorbed on a gold (Au) support and incubated in charged monomers (4-Styrenesulfonate sodium and 3-Hydroxytyraminium chloride). The protein was further eliminated by enzymatic activity, leaving behind vacant sites for subsequent rebinding. Electrochemical detection (ii) was achieved on an Au working electrode, designed on commercial screen-printed electrodes. Raman spectroscopy, atomic force microscopy and ellipsometric readings were used to follow the chemical modification of the Au surface. The ability of the material to rebind CA15-3 was monitored by electrochemical techniques. The device displayed linear responses to CA15-3 ranging from 0.25 to 10.00 U/mL, with detection limits of 0.05 U/mL. Accurate results were obtained by applying the sensor to the analysis of CA15-3 in PBS buffer and in serum samples. This biosensing device displayed successful features for the detection of CA 15–3 and constitutes a promising tool for breast cancer screening procedures in point-of-care applications. Moreover, its scale-up seems feasible as it contains a plastic antibody assembled <i>in situ</i>, in less than 1 minute, and the analysis of serum takes less than 30 minutes.</p></div

Tityus serrulatus Scorpion Venom: In Vitro Tests and Their Correlation with In Vivo Lethal Dose Assay

Scorpion stings are the main cause of human envenomation in Brazil and, for the treatment of victims, the World Health Organization (WHO) recommends the use of antivenoms. The first step to achieve effective antivenom is to use a good quality venom pool and to evaluate it, with LD50 determination as the most accepted procedure. It is, however, time-consuming and requires advanced technical training. Further, there are significant ethical concerns regarding the number of animals required for testing. Hence, we investigated the correspondence between LD50 results, in vitro assays, and a strong correlation with proteolytic activity levels was observed, showing, remarkably, that proteases are potential toxicity markers for Tityus serrulatus venom. The comparison of reversed-phase chromatographic profiles also has a potential application in venoms’ quality control, as there were fewer neurotoxins detected in the venom with high LD50 value. These results were confirmed by mass spectrometry analysis. Therefore, these methods could precede the LD50 assay to evaluate the venom excellence by discriminating—and discarding—poor-quality batches, and, consequently, with a positive impact on the number of animals used. Notably, proposed assays are fast and inexpensive, being technically and economically feasible in Tityus serrulatus venom quality control to produce effective antivenoms

Autolytic Mycobacterium leprae Hsp65 fragments may act as biological markers for autoimmune diseases

Investigating the proteolytic activity of the recombinant Mycobacterium leprae Heat Shock Protein of 65 kDa (rHsp65), chaperonin 2 (cpn2), we observed that it displays high instability. The fragmentation process starts at the C-terminus followed by progressive degradation of the N-terminus, which leads to a stable fragment comprising the middle region of the molecule. Urea was able to prevent autolysis, probably due to its denaturing action, while EDTA increased degradation levels indicating the need for metal ions. Peptides originated from autolysis were purified and analyzed by mass spectrometry, generating a continuous map. Since the bacteria and mammalian Hsp60 are known to be targets of the immune response and have been implicated in autoimmune diseases and chronic inflammation, the in vivo effect of rHsp65 peptides was evaluated in the spontaneous Systemic Lupus Erythematosus (SLE) model developed by the (NZB/NZW)F(1) mouse hybrids, and their individual anti-rHsp65 IgG2a/IgG1 antibody titer ratio was determined. The results showed orientation toward a T(H)1 responsiveness, and the treatment with the rHsp65 peptides diminished the environmental variance of the survival time of treated animals. These results outline the fact that environmental factors may also act through the modified stability expression of Heat Shock Proteins intervening during autoimmune processes. (C) 2011 Elsevier Ltd. All rights reserved.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[2008/2899-2]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Cloning, expression and characterisation of an HtrA-like serine protease produced in vivo by Mycobacterium leprae

Members of the high temperature requirement A (HtrA) family of chaperone proteases have been shown to play a role in bacterial pathogenesis. In a recent report, we demonstrated that the gene ML0176, which codes for a predicted HtrA-like protease, a gene conserved in other species of mycobacteria, is transcribed by Mycobacterium leprae in human leprosy lesions. In the present study, the recombinant ML0176 protein was produced and its enzymatic properties investigated. M. leprae recombinant ML0176 was able to hydrolyse a variety of synthetic and natural peptides. Similar to other HtrA proteins, this enzyme displayed maximum proteolytic activity at temperatures above 40°C and was completely inactivated by aprotinin, a protease inhibitor with high selectivity for serine proteases. Finally, analysis of M. leprae ML0176 specificity suggested a broader cleavage preference than that of previously described HtrAs homologues. In summary, we have identified an HtrA-like protease in M. leprae that may constitute a potential new target for the development of novel prophylactic and/or therapeutic strategies against mycobacterial infections

Novel CD28 antagonist mPEG PV1-Fab’ mitigates experimental autoimmune uveitis by suppressing CD4+ T lymphocyte activation and IFN-γ production

<div><p>Autoimmune Uveitis is an important chronic inflammatory disease and a leading cause of impaired vision and blindness. This ocular autoimmune disorder is mainly mediated by T CD4⁺ lymphocytes poising a T_H1 phenotype. Costimulatory molecules are known to play an important role on T cell activation and therefore represent interesting therapeutical targets for autoimmune disorders. CD28 is the prototypical costimulatory molecule for T lymphocytes, and plays a crucial role in the initiation, and maintenance of immune responses. However, previous attempts to use this molecule in clinical practice achieved no success. Thus, we evaluated the efficacy of mPEG PV1-Fab’ (PV1), a novel selective CD28 antagonist monovalent Fab fragment in the treatment of Experimental Autoimmune Uveitis (EAU). Here, we showed that PV1 treatment decreases both average disease score and incidence of EAU. A decrease in the activation profile of both T CD4⁺ and T CD8⁺ eye-infiltrating lymphocytes was evidenced. In the periphery, T CD4⁺ cells from PV1-treated mice also showed a decrease in their activation status, with reduced expression of CD69, CD25, and PD-1 molecules. This suppression was not dependent on Treg cells, as both their frequency and absolute number were lower in PV1-treated mice. In addition, frequency of CD4⁺IFN-γ⁺ T cells was significantly lower in PV1-treated group, but not of IL-17-producing T cells. Moreover, after specific restimulation, PV1 blockade selectively blocked IFN-γ production by CD4⁺ lymphocytes Taken together, our data suggest that mPEG PV1-Fab’ acts mainly on IFN-γ-producing CD4⁺ T cells and emphasize that this specific CD28 blockade strategy is a potential specific and alternative tool for the treatment of autoimmune disorders in the eye.</p></div