Development of vaccines for HIV-1: relevance of subtype-specific cellular immunity

Han pasado casi 30 años de la detección de los primeros casos de infección con HIV-1 y aún no se ha conseguido desarrollar una vacuna efectiva y segura. A pesar del impacto positivo sobre la pandemia que se ha conseguido gracias a los avances en la terapia antirretroviral (TARV), el HIV/sida sigue constituyendo un grave problema para la salud pública, especialmente en los países en desarrollo, donde es difícil el acceso al tratamiento. En el mundo, 33 millones de personas viven con el virus del sida, mientras que en la Argentina se calcula que habría unos 120 000 infectados. Uno de los desafíos para lograr una vacuna contra el HIV es la variabilidad viral. El grupo M, responsable de la pandemia, se encuentra dividido en 10 subtipos y varios sub-subtipos, además de las 48 formas recombinantes circulantes y más de cien formas recombinantes únicas. La epidemia de HIV en nuestro país es tan compleja como en el resto del mundo, con la co-circulación principalmente de virus pertenecientes al subtipo B y recombinantes BF (CRF12_BF y derivadas). A pesar de la cantidad de trabajos dedicados a la caracterización de la respuesta inmune y al desarrollo de vacunas, no queda claro cuál es el impacto de la variabilidad en la elección del antígeno. Trabajos realizados en nuestro laboratorio demuestran el papel que juega la inmunidad celular con respecto a las variantes recombinantes BF, tanto en humanos como en modelos animales. Estos resultados son de importancia en el desarrollo de futuras vacunas para nuestra región.It has been almost 30 years since the detection of the first HIV-1 cases and yet an effective and safe vaccine has not been developed. Although, advances in antiretroviral therapy (HAART) have produced a major impact on the pandemic, and even though HIV/aids remains a major concern for developing countries, where access to therapy is limited. The last report from UNAIDS notified 33 million people living with HIV/aids, worldwide, while in Argentina it is estimated that 120 000 persons have been infected. One of the challenges to address and ultimately overcome when developing a vaccine is the high variability of HIV-1. The M group, responsible for the pandemic, is divided into 10 subtypes and several sub-subtypes, in addition to the 48 circulating recombinant forms (CRF) and over one hundred unique recombinant forms (URF). The HIV epidemic in Argentina is as complex as in the rest of the world, characterized by the high prevalence of infections caused by subtype B and BF variants. Despite the wide range of publications focused on the immune response against HIV as well as to vaccine development, how to overcome variability on vaccine antigen selection is still unclear. Studies performed in our laboratory showed the impact of the immunogenicity of BF recombinant variants, both in humans and in animal models. These results are of great concern in vaccine development for our region.Fil: Rodríguez, Ana María. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; ArgentinaFil: Turk, Gabriela Julia Ana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pascutti, María Fernanda. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Falivene, Juliana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gherardi, Maria Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentin

Inclusão escolar de alunos portadores de Transtorno do Espectro Autista na educação infantil: uma revisão sistemática: School inclusion of students with Autistic Spectrum Disorder in early childhood education: a systematic review

Este artigo debate o problema da inclusão escolar de crianças com transtorno do espectro autista (TEA). Para estabelecer o debate, foi feito um levantamento bibliográfico e referencial para uma revisão sistemática do tema. O objetivo é clarificar os conceitos de inclusão escolar e TEA para debater como é feito o processo educacional de crianças com TEA. Sendo assim, a partir da pesquisa científica de descritores como “inclusão escolar”, “transtorno do espectro autista”, foi observado, pelos diversos autores trabalhados, que ainda há muito o que se debater e trabalhar para que ocorra a inclusão escolar de crianças com TEA. Apesar das muitas tentativas, erros e acertos, o tema ainda é pouco trabalhado e divulgado, visto que há poucos profissionais capacitados na área

Diagnóstico diferencial da Síndrome de Takotsubo e infarto agudo do miocárdio: uma revisão sistemática: Differential diagnosis of Takotsubo Syndrome and acute myocardial infarction: a systematic review

A cardiomiopatia de Takotsubo e o infarto agudo do miocárdio compartilham apresentação clínica e risco de morte semelhantes, embora uma das diferenças mais importantes seja a ausência de doença coronariana obstrutiva na cardiomiopatia de Takotsubo. Neste estudo, tem-se como objetivo analisar a literatura disponível avaliando o diagnóstico diferencial entre pacientes com CTT em comparação com pacientes com infarto agudo do miocárdio. Para isso, foi realizada uma revisão sistemática, utilizando-se a Pubmed e a Medline como base de dados. A partir da análise dos estudos e interpretação de suas principais descobertas, concluiu-se que para pacientes com CTT, outras condições e comorbidades, em vez de apenas dislipidemia e/ou outros fatores de risco estabelecidos, sejam responsáveis por um risco de morte comparável ao de IAM. No entanto, as conclusões desse estudo têm várias limitaçõe

Impact of Viral Infections on Hematopoiesis: From Beneficial to Detrimental Effects on Bone Marrow Output

The ability of the bone marrow (BM) to generate the copious amounts of blood cells required on a daily basis depends on a highly orchestrated process of proliferation and differentiation of hematopoietic stem and progenitor cells (HSPCs). This process can be rapidly adapted under stress conditions, such as infections, to meet the specific cellular needs of the immune response and the ensuing physiological changes. This requires a tight regulation in order to prevent either hematopoietic failure or transformation. Although adaptation to bacterial infections or systemic inflammation has been studied and reviewed in depth, specific alterations of hematopoiesis to viral infections have received less attention thus far. Viruses constantly pose a significant health risk and demand an adequate, balanced response from our immune system, which also affects the BM. In fact, both the virus itself and the ensuing immune response can have a tremendous impact on the hematopoietic process. On one hand, this can be beneficial: it helps to boost the cellular response of the body to resolve the viral infection. But on the other hand, when the virus and the resulting anti-viral response persist, the inflammatory feedback to the hematopoietic system will become chronic, which can be detrimental for a balanced BM output. Chronic viral infections frequently have clinical manifestations at the level of blood cell formation and we summarize which viruses can lead to BM pathologies, like aplastic anemia, pancytopenia, hemophagocytic lymphohistiocytosis (HLH), lymphoproliferative disorders and malignancies. Regarding the underlying mechanisms, we address specific effects of acute and chronic viral infections on blood cell production. As such, we distinguish four different levels in which this can occur: 1.) direct viral infection of HSPCs, 2.) viral recognition by HSPCs, 3.) indirect effects on HSPCs by inflammatory mediators and 4.) the role of the BM microenvironment on hematopoiesis upon virus infection. In conclusion, this review provides a comprehensive overview on how viral infections can affect the formation of new blood cells, aiming to advance our understanding of the underlying cellular and molecular mechanisms to improve the treatment of BM failure in patients

Quantitative and qualitative analysis of bone marrow CD8+ T cells from different bones uncovers a major contribution of the bone marrow in the vertebrae.

Bone marrow (BM) plays an important role in the long-term maintenance of memory T cells. Yet, BM is found in numerous bones throughout the body, which are not equal in structure, as they differ in their ratio of cortical and trabecular bone. This implies, that BM cells within different bones are subjected to different microenvironments, possibly leading to differences in their frequencies and function. To address this, we examined BM from murine tibia, femur, pelvis, sternum, radius, humerus, calvarium and the vertebrae and analyzed the presence of effector memory (TEM), central memory (TCM) and naïve (TNV) CD8+ T cells. During steady state conditions, the frequency of the total CD8+ T cell population was comparable between all bones. Interestingly, most CD8+ T cells were located in the vertebrae, as it contained the highest amount of BM cells. Furthermore, the frequencies of TEM, TCM and TNV cells were similar between all bones, with a majority of TNV cells. Additionally, CD8+ T cells collected from different bones similarly expressed the key survival receptors IL-7Rα and IL-15Rβ. We also examined BM for memory CD8+ T cells with a tissue-resident memory phenotype, and observed that approximately half of all TEM cells expressed the retention marker CD69. Remarkably, in the memory phase of acute infection with the lymphocytic choriomeningitis virus (LCMV), we found a massive compositional change in the BM CD8+ T cell population, as the TEM cells became the dominant subset at the cost of TNV cells. Analysis of Ki-67 expression established that these TEM cells were in a quiescent state. Finally, we detected higher frequencies of LCMV-specific CD8+ T cells in BM compared to spleen and found that BM in its entirety contained five-fold more LCMV-specific CD8+ T cells. In conclusion, although infection with LCMV caused a dramatic change in the BM CD8+ T cell population, this did not result in noticeable differences between BM collected from different bones. Our findings suggest that in respect to CD8+ T cells, BM harvested from a single bone is a fair reflection of the rest of the BM present in the murine body

Adrenal steroids modulate the phenotype and function of M. tuberculosis-stimulated human dendritic cells

Cell-mediated immunity, cytokines induced during the specific immune response and T-cell populations are crucial factors for containing Mycobacterium tuberculosis infection. Recent reports suggest a cross-regulation between adrenal steroids (glucocorticoids and dehydroepiandrosterone, DHEA) and the function of antigen-presenting cells (APCs). Therefore, we investigated the role of adrenal hormones on the functional capacity of M. tuberculosis-induced dendritic cells (DCs). Cortisol significantly inhibited the functions of M. tuberculosis-induced DCs. Interestingly, the presence of DHEA enhanced the M. tuberculosis-induced expression of MHC I, MHC II and CD86 and also increased ERK1/2 phosphorylation. Moreover, DHEA improved the production of IL-12 in response to M. tuberculosis stimulation, diminished IL-10 secretion and could not modify TNF-α synthesis. Importantly, we observed that DHEA enhanced the antigen-specific T-cell proliferation and IFN-γ production induced by M. tuberculosis-stimulated DC. These data show for the first time the relevance of the adrenal axis (especially of DHEA) in the modulation of DC function in the context of tuberculosis, a disease where the induction of a Th1 environment by APCs is crucial for the development of an effective immune response to the mycobacteria.Fil: Angerami, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina; Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentina;Fil: Suárez, Guadalupe Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina;Fil: Pascutti, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina;Fil: Salomon, Horacio Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina; Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología; Argentina;Fil: Bottasso, Oscar Adelmo. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Instituto de Inmunología; Argentina;Fil: Quiroga, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina; Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología. Centro Nacional de Referencia del Sida; Argentina

Constitutive GITR Activation Reduces Atherosclerosis by Promoting Regulatory CD4+ T-Cell Responses-Brief Report

Glucocorticoid-induced tumor necrosis factor receptor family-related protein (GITR) is expressed on CD4(+) effector memory T cells and regulatory T cells; however, its role on these functionally opposing cell types in atherosclerosis is not fully understood. Low-density lipoprotein receptor-deficient mice (Ldlr(-/-)) were lethally irradiated and reconstituted with either bone marrow from B-cell-restricted Gitrl transgenic mice or from wild-type controls and fed a high-cholesterol diet for 11 weeks. Chimeric Ldlr(-/-) Gitrl(tg) mice showed a profound increase in both CD4(+) effector memory T cells and regulatory T cells in secondary lymphoid organs. Additionally, the number of regulatory T cells was significantly enhanced in the thymus and aorta of these mice along with increased Gitrl and Il-2 transcript levels. Atherosclerotic lesions of Ldlr(-/-) Gitrl(tg) chimeras contained more total CD3(+) T cells as well as Foxp3(+) regulatory T cells overall, leading to significantly less severe atherosclerosis. These data indicate that continuous GITR stimulation through B cell Gitrl acts protective in a mouse model of atherosclerosis by regulating the balance between regulatory and effector memory CD4(+) T cell

Enhanced CD8 T Cell Responses through GITR-Mediated Costimulation Resolve Chronic Viral Infection

<div><p>Chronic infections are characterized by the inability to eliminate the persisting pathogen and often associated with functional impairment of virus-specific T-cell responses. Costimulation through Glucocorticoid-induced TNFR-related protein (GITR) can increase survival and function of effector T cells. Here, we report that constitutive expression of GITR-ligand (GITRL) confers protection against chronic lymphocytic choriomeningitis virus (LCMV) infection, accelerating recovery without increasing pathology. Rapid viral clearance in GITRL transgenic mice coincided with increased numbers of poly-functional, virus-specific effector CD8+ T cells that expressed more T-bet and reduced levels of the rheostat marker PD-1. GITR triggering also boosted the helper function of virus-specific CD4 T cells already early in the infection, as was evidenced by increased IL-2 and IFNγ production, and more expression of CD40L and T-bet. Importantly, CD4-depletion experiments revealed that the expanded pool of virus-specific effector CD8 T cells and the ensuing viral clearance in LCMV-infected GITRL tg mice was entirely dependent on CD4 T cells. We found no major differences for NK cell and regulatory T cell responses, whereas the humoral response to the virus was increased in GITRL tg mice, but only in the late phase of the infection when the virus was almost eradicated. Based on these findings, we conclude that enhanced GITR-triggering mediates its protective, anti-viral effect on the CD8 T cell compartment by boosting CD4 T cell help. As such, increasing costimulation through GITR may be an attractive strategy to increase anti-viral CTL responses without exacerbating pathology, in particular to persistent viruses such as HIV and HCV.</p></div