Evaluación de formulaciones inmunoterapéuticas experimentales en el modelo hibrido murino de Reaccion del Injerto contra el Hospedador / Evaluation of experimental immunotherapeutic formulations in the hybrid murine model of Graft-versus-Host Reaction

Introducción: La Enfermedad del Injerto Contra el Hospedador es la complicación más frecuente de los Trasplantes de Células Madre Hematopoyéticas y de todos los trasplantes que contengan células inmunocompetentes alogénicas, el 100 por ciento la padecen y cerca del 30 por ciento mueren por su causa; una proporción alta de casos son esteroide-refractarios, asimismo otras medidas inmunosupresoras modernas fracasan. En los campos de la Inmunoterapia y la Vaccinología también existe una escasez preocupante de inmunomoduladores de origen biológico potentes, efectivos, seguros y de amplio espectro. Existe un modelo híbrido murino de gran utilidad metodológica para estudios experimentales. Objetivo: Evaluar dos formulaciones novedosas de origen biotecnológico, una de ellas inmunopotenciadora y otra inmunosupresora, desarrolladas como cocleatos. Material y Métodos: Mediante Microscopia Electrónica y RT-PCR se caracterizaron las formulaciones como nanopartículas y su capacidad de regular la expresión del ARNm de linfoquinas definitorias de sus perfiles, respectivamente. Empleando el modelo de Enfermedad del Injerto Contra el Hospedador en ratón híbrido F1 (CBAxC57BL), se evaluó su carácter inmunomodulador in vivo . Resultados: Partiendo de los proteoliposomas de Neisseria meningitidis, se obtuvieron dos formulaciones en forma de cocleatos, ambas con diámetros de partícula inferior a 100nm. La Formulación 1mostró un perfil proinflamatorio con potente capacidad de aumentar el IFNγ y el TNFα y potenció el Índice de Bazo hasta 2,05 en el modelo EICH con p=0,0002. La Formulación 2 mostró un perfil supresor-regulatorio con potente capacidad de aumentar la IL-10 y el TGFβ y además de suprimir la producción de TNFα. En el modelo usado, esta formulación, suprimió el Índice de Bazo de manera dosis dependiente y con alta significación estadística. Se corroboró el conocido perfil de seguridad y ausencia de reactogenicidad de ambas formulaciones. Conclusiones: Ambas formulaciones tienen potencial aplicación en los campos de la terapia de Enfermedad del Injerto Contra el Hospedador en otras patologías y en Vaccinología. Los resultados obtenidos en el presente trabajo fundamentan la conveniencia de continuar el desarrollo farmacéutico y completar la preclínica de ambas formulaciones(AU)

Introduction: Graft-versus-host disease is the most frequent complication of Hematopoietic Stem Cell Transplants and all transplants containing allogeneic immunocompetent cells; 100 percent of patients suffer from this complication and about 30 percent die for this particular cause. A high proportion of cases are steroid-refractory; likewise, other modern immunosuppressive measures fail. In the fields of Immunotherapy and Vaccinology, there is also a worrying shortage of powerful, effective, safe and broad spectrum immunomodulators of biological origin. There is a hybrid murine model of great methodological utility for experimental studies. Objective: To evaluate two novel formulations of biotechnological origin: an immunopotentiator formulation and an immunosuppressive one, which were developed as cochleates. Material and Methods: The formulations assayed by Electron Microscopy and RT-PCR were characterized as nanoparticles and for their capacity to regulate lymphokine mRNA expression profile, respectively. The immunomodulatory character was evaluated in vivo using Graft-versus-host disease in (CBAxC57BL) F1 hybrid mice. Results: Starting from the proteoliposomes derived from Neisseria meningitides, two cochleate formulations were obtained, both with particle diameters below 100 nm. Formulation 1 showed a proinflammatory profile with potent capacity to increase IFNγ and TNFα, and potentiated the Spleen Index up to 2.05 in the GVDH model with p = 0.0002. Formulation 2 showed a suppressor/regulatory profile with potent capacity to increase IL-10 and TGFβ and suppress the production of TNFα. In the model used, this formulation suppressed the Spleen Index in a dose-dependent manner with high statistical significance. The known safety profile and absence of reactogenicity of both formulations was corroborated. Conclusions: Both formulations have potential application in the fields of GVHD therapy and other pathologies as well as in Vaccinology. The results obtained in the present work suggest the usefulness to continue with the pharmaceutical development and complete the preclinical studies of both formulations(AU)

Development and use a novel combined in-vivo and in-vitro assay for anti-inflammatory and immunosuppressive agents

Contact hypersensitivity [CHS] mouse model induced by 2, 4-dinitrofluorobenzene [DNFB] is thought to be a T helper 1 [Th1]-dominant response and used for investigating anti-inflammatory and immunosuppressive agents. However, it is hardly used for screening large-scale drugs because of the large number of animals and complex mechanisms involved in-vivo. In this study, we focused on whether T lymphocytes from CHS mouse model could maintain the state of immune response in-vitro and explored a suitable time for drugs screening. The results showed that CD4[+] T cells of CHS mice were higher compared with those in normal group. The expression of T-bet and GATA3 showed a Th1 shift and the levels of interleukin [IL]-2 and IL-4 also showed similar trend. Furthermore, IL-6 produced by T lymphocytes from CHS mice had a high level too. Then, we detected the effects of dexamethasone [DEX], cyclosporine A [CsA] and mycophenolate mofetil [MMF] on T lymphocytes in-vitro, and the data displayed that these immunosuppressive drugs could all inhibit the proliferation of T lymphocytes significantly. These findings suggested that T lymphocytes from CHS mice could mimic a similar immune response in-vitro, and it's also a suitable method for screening anti-inflammatory and immunosuppressive agents

Vacunas en reumatología: seguridad y eficacia, uso de drogas biológicas y desarrollo de autoinmunidad / Vaccines in rheumatology: safety and efficacy, use of biological drugs and autoimmune development

La presente revisión compendia los estudios existentes sobre el uso de vacunas en pacientes con enfermedades reumatológicas, tanto en lo referente a su indicación, seguridad, inmunogenicidad, aparición de exacerbaciones, efecto sobre los tratamientos farmacológicos inmunosupresores empleados y de éstos sobre la respuesta a la vacunación Los estudios muestran que cuando una vacuna es correctamente indicada, constituye una valiosa herramienta en la protección de pacientes inmunodeprimidos. Además, no generan exacerbaciones clínicas de la enfermedad autoinmune y pueden inducir una adecuada respuesta inmunológica aunque ésta puede ser subóptima en comparación con controles sanos. Finalmente se hace referencia al desarrollo de autoinmunidad con posterioridad a la vacunación.

The present review sumnarizes the existing studies about the use of vaccines in patients with autoimmune rheumatic diseases, both with reference to indication, safety inmunogenicity flare development, effect on inmunosuppressive pharmacologic treatment used, and their response to the vaccinations. Studies show that when a vaccine is correctly indicated, it represents a valuable instrument for the protection of immunedepressed patients. Besides, it does not generate clinical exacerbation of autoimmune diseases and can induce a suitable immunologic response, although this is can be lower than that of healthy controls. Finally, we refer to the development of autoimmunity after vaccination.

Susceptible hosts: a resort for parasites right in the eye of the immune response

Trypanosomatid protozoan parasites express an aggressive strategy of parasitism by infecting host macrophages and inducing extensive T-lymphocyte activation. One goal of such strategy is to drive the immune response of genetically susceptible hosts to a state of unresponsiveness regarding parasite killing. Unresponsiveness is achieved through different mechanisms, depending on the parasite species. In this brief review, recent findings on the molecular and cellular bases of the parasites' exploitation of host immune responses are discussed.

The immune response to malaria sporozoite antigens in animal models and humans: a retrospective overview and present goals

Research and ultimate goals of our sdutides in mamaria immunity is reviewed. A new experimental vector for Plasmodium gallinaceum, an avian malaria, the mosquito Aedes fluviatilis is described. Sporozoites recovered from oocyst (OoS), before they enter salivary glands, are infective for chickens although somewhat less so than the mature salivary gland sporozoites (SGS). The repetitive portion of the circumsporozoite (CS) membrane protein is not responsible for migration/maturation of the OoS into the salivary glands or for infectivity for the vertebrate although present in both populations. The older sporozoites, recovered from mosquitos 4-5 weeks after infection, gradually lose infectivity for chickens. An age-dependent response of chickens to a sporozoite-induced malaria is described, young animals being more susceptible. Monoclonal antibodies (MoAb) have been produced against surface antigens of P. gallinaceum sporozoites, epecific for OoS and SGS antigens, as judged by indirect immunofluorescence and circumsporozoite precipitation tests. By Western blot or by competitive ELISA, these MoAbs recognize the repeat epitope of the CS protein, two polypeptides of molecular weight 64 an 76 kDa, as do the sera from mice immunized with sporozoites. Tested against live sporozoites, these MoAb showed variable protective activity, some of them totally inhibiting parasite infectivity in in vivo and in vitro tests. Cross-reactivity occurred between these MoAb and sporozoites of Plasmodium berghei as well as with their CS protein repeats but no cross-protection was demonstrated against this rodent malaria. Our studies in human malaria in the Amazon area are restricted to the last two years, and to a small sample (180) of individuals recently exposed to transmission of Plasmodium falciparum and P. vivax. A variable but low number (9-30 percent) had anti-CS antibodies and a positive cellular immune response (30-40 percent) in vitro to recombinant CS proteins (of P. falciparum and P. vivax). We found no correlation between these two parameters; between antigen responsiveness and time of exposure to malaria transmission (up to ten years); or between the number of previous malaria infections. In previous studies we showed that individulas who had been exposed but did not acquire malaria, in a focal area of transmission in Minas Gerais, had antisporozoite antibodies...

Cadaveric transplantation.

Transplantation is already the optimum treatment for terminal renal failure. Donor organ shortage means that there are large number of patients on dialysis awaiting this treatment. This has in some countries led to unacceptable unscrupulous practices of live non-related graft donation. The outcome of graft and patient after transplantation has improved significantly based on a better understanding of immunopathology, immunosuppression and tissue typing. The future is promising and xenografting may well solve the organ shortage but undoubtedly will raise other issues.