Comparative evaluation of memory T cells in COVID-19 patients and the predictive role of CD4+CD8+ double positive T lymphocytes as a new marker

SUMMARY BACKGROUND: The COVID-19 pandemic has affected the entire world, posing a serious threat to human health. T cells play a critical role in the cellular immune response against viral infections. We aimed to reveal the relationship between T cell subsets and disease severity. METHODS: 40 COVID-19 patients were randomly recruited in this cross-sectional study. All cases were confirmed by quantitative RT-PCR. Patients were divided into two equivalent groups, one severe and one nonsevere. Clinical, laboratory and flow cytometric data were obtained from both clinical groups and compared. RESULTS: Lymphocyte subsets, CD4+ and CD8+ T cells, memory CD4+ T cells, memory CD8+ T cells, naive CD4+ T cells, effector memory CD4+ T cells, central memory CD4+ T cells, and CD3+CD4+ CD25+ T cells were significantly lower in severe patients. The naive T cell/CD4 + EM T cell ratio, which is an indicator of the differentiation from naive T cells to memory cells, was relatively reduced in severe disease. Peripheral CD4+CD8+ double-positive T cells were notably lower in severe presentations of the disease (median DP T cells 11.12 µL vs 1.95 µL; p< 0.001). CONCLUSIONS: As disease severity increases in COVID-19 infection, the number of T cell subsets decreases significantly. Suppression of differentiation from naive T cells to effector memory T cells is the result of severe impairment in adaptive immune functions. Peripheral CD4+CD8+ double-positive T cells were significantly reduced in severe disease presentations and may be a useful marker to predict disease severity.

RESUMO OBJETIVO: A pandemia de COVID-19 tem afetado o mundo todo, constituindo uma ameaça grave para a saúde humana. As células T desempenham um papel crítico na imunidade celular contra infecções virais. Procuramos desvendar a relação entre sub grupos de células T e a severidade da doença. MÉTODOS: Um total de 40 pacientes com COVID-19 foram aleatoriamente recrutados para o presente estudo transversal. Todos os casos foram confirmados por RT-PCR quantitativo. Os pacientes foram divididos em dois grupos equivalentes, um grave e um não-grave. Os dados da avaliação clínica, laboratorial e da citometria de fluxo foram obtidos para ambos os grupos e comparados. RESULTADOS: Os subconjuntos de linfócitos, células T CD4+ e CD8+, células T de memória CD4+, células T de memória CD8+, células T CD4+ virgens, células T efetoras CD4+, células T de memória central CD4+ e células T CD3+ CD4+ CD25+ estavam significativamente mais baixas nos pacientes graves. A razão células T virgens/células T efetoras TCD4+, que é um indicador da diferenciação entre células T virgens e células de memória, estava relativamente reduzida em casos graves da doença. As células T duplo-positivas CD4+CD8+ periféricas estavam notavelmente mais baixas em casos graves da doença (mediana das células T DP: 11,12 µL vs. 1,95 µL; p< 0,001). CONCLUSÃO: Conforme aumenta a gravidade da doença nos casos de COVID-19, o número de subconjuntos de células T diminui significativamente. A supressão da diferenciação de células T virgens para células T efetoras é o resultado do comprometimento grave das funções imunológicas adaptativas. As células T duplo-positivas CD4+CD8+ periféricas estavam notavelmente mais baixas em casos graves da doença e podem ser um marcador útil para predizer a severidade da doença.

Cinética de muerte de linfocitos en diabetes mellitus tipo 1 y su posible asociación con miR-146a y miR-155 / Kinetics of cell death in type 1 diabetes mellitus and their possible association with miR-146a and miR-155

Aim: Analyze mi-146a and miR-155 expression and its correlation with the apoptosis of lymphocytes T in T1D and control patient. Patients and Methodology: 17 T1D patients (5 children between 8-14 yr and 12 adults between 19-29 yr). Activated and not activated peripheral mononuclear cells were studied were studied. Cellular activation with anti-CD3 and primary culture with interleukyne-2 by 5 days. Apoptosis assays through flow cytometry. miRNA through Taqman probes. Statistical analysis through Kruskal-Wallis and post-hoc Dunn's test. Results: Composition of virgin and memory T CD4 cells showed significant differences for stimulus response in control group (p = 0,0004). Increased memory cells count in control group activated by 7 days than basal (p = 0,0047). For early apoptosis differences were observed in days 3 and 7 with and without activation (p = 0,001). AICD apoptosis showed increases in control group after re-stimulation through TCR (p= 0,03). miR-146a expression was lower in recent-onset T1D children vs recent-onset DM1 adults (p = 0,0167). Conclusion: This study shows a differential miR-146a expression in T1D children with respect to T1D adult patients, diminished AICD mechanism in T1D and altered CD4+CD45RA-CD45R0+ memory cells generation in T1D adult patients.

Aplicación de la nanobiotecnología con el sistema CRISPR-cas / Application of the nanobiotechnology with the system CRISP-Cas

Resumen Introducción: La nanobiotecnología y la biología sintética son ciencias que impactan en la actualidad con el lanzamiento de aplicaciones innovadoras y beneficiosas para el ser humano, estas ciencias se han fusionado para fabricar nuevos componentes para la construcción de células totalmente artificiales y la creación de biomoléculas sintéticas. Objetivo: Conocer las aplicaciones de la nanobiotecnología relacionadas con el uso del sistema CRISPR/Cas en el almacenamiento de información en el ADN bacteriano y alternativas terapéuticas. Materiales y métodos: Se realizó una revisión bibliográfica sobre las principales aplicaciones de la nanobiotecnología, en las bases de datos ScienceDirect, SciELO, PubMed y en revistas como: Nature biotechnology, Biochemistry, Science y Journal Microbiology. Resultados: La revisión de literatura describe y analiza las nuevas aplicaciones nanobiotecnológicas utilizadas para escribir información en el código genético de las células bacterianas, en el que se emplean el sistema basado en repeticiones palindrómicas cortas agrupadas y regularmente interespaciadas (CRISPR/Cas) y la producción de ADN sintético, así como las alternativas terapéuticas relacionadas con la terapia génica. Conclusión: Entre las aplicaciones nanobiotecnológicas se han demostrado dos métodos para grabar información en el ADN de células bacterianas, de Escherichia coli y Sulfolobus tokodai vinculados con el empleo del sistema CRISPR/Cas y la producción de ADN sintético, así como el uso del CRISPR/Cas en la terapia génica y celular.

Abstract Introduction: Nanobiotechnology and synthetic biology are sciences that impact today with the launching of innovative and beneficial applications for the human being. These sciences have been amalgamated to manufacture new components for the construction of totally artificial cells and the creation of synthetic biomolecules. Objective: To know the applications of nanobiotechnology related to the use of the system CRISPR/Cas in the storage of bacterial DNA and therapeutic alternatives. Materials and methods: A bibliographical review on the main applications of nanobiotechnology was carried out in ScienceDirect, SciELO, PubMed databases and in magazines such as: Nature Biotechnology, Biochemistry, Science and Journal Microbiology. Results: The literature review describes and analyzes the new nanobiotechnology applications used to write information in the genetic code of bacterial cells, in which the system is used based on short grouped and regularly interspaced palindromic repetitions (CRISPR/Cas) and the production of synthetic DNA, as well as therapeutic alternatives related to gene therapy. Conclusion: Among the nanobiotechnology applications, two methods to record information in the DNA of bacterial cells Escherichia coli and Sulfolobus Tokodai have been shown, which are linked to the use of the system CRISPR/Cas and the production of synthetic DNA, as well as the use of CRISPR/Cas in gene and cellular therapy.

Immune development in HIV-exposed uninfected children born to HIV-infected women

ABSTRACT Immunological and clinical findings suggestive of some immune dysfunction have been reported among HIV-exposed uninfected (HEU) children and adolescents. Whether these defects are persistent or transitory is still unknown. HEU pediatric population at birth, 12 months, 6-12 years were evaluated in comparison to healthy age-matched HIV-unexposed controls. Plasma levels of LPS, sCD14, cytokines, lymphocyte immunophenotyping and T-cell receptor excision circles (TREC) were assessed. HEU and controls had similar LPS levels, which remained low from birth to 6-12 years; for plasma sCD14, IL-2, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-17, IFN-γ, TNF-α, G-CSF, GM-CSF and MCP-1, which increased from birth to 12 months and then decreased at 6-12 years; and for TREC/106 PBMC at birth in HEU and controls. By contrast, plasma MIP-1β levels were lower in HEU than in controls (p=0.009) at 12 months, and IL-4 levels were higher in HEU than controls (p=0.04) at 6-12 years. Immune activation was higher in HEU at 12 months and at 6-12 years than controls based on frequencies of CD38+HLA-DR+CD8+T cells (p=0.05) and of CD38+HLA-DR+CD4+T cells (p=0.006). Resting memory and activated mature B cells increased from birth to 6-12 years in both groups. The development of the immune system in vertically HEU individuals is comparable to the general population in most parameters, but subtle or transient differences exist. Their role in influencing clinical incidences in HEU is unknown.

B cells expressing IL-10 mRNA modulate memory T cells after DNA-Hsp65 immunization

In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.

Evolução pós-tratamento de pacientes infectados por duas espécies de Leishmania do subgênero Viannia / Post-treatment evolution of patients infected by Leishmania species of subgenus Viannia: L. braziliensis and L. naiffi

A principal estratégia para controlar a leishmaniose tegumentar Americana (LTA) seria a imunoprofilaxia. Entretanto, até o momento ainda não existe uma vacina, dificultando o controle da doença. [...] O propósito desta tese foi avaliar a evolução pós-tratamento de casos de infecção por Leishmania naiffi (Ln) e L. braziliensis (Lb) sob dois aspectos diferentes: 1) descrever uma série de casos de LTA causados por Ln selecionados dentre trinta pacientes atendidos na Fundação de Medicina Tropical Dr. Heitor Vieira Dourado(FMT-HVD), Manaus, no período de 2011 a 2013. 2) avaliar se a assinatura imunológica, em termos de subclasses de imunoglobulina e perfil de diferenciação celular e memória, é similar entre pacientes de Lb com até 26 anos de cura após tratamento com dois diferentes esquemas terapêuticos com antimônio. Foram estudados 43 pacientes curados de leishmaniose cutânea (LCC), sendo estes divididos em dois grupos: pacientes de LCC acompanhados desde a fase ativa até três anos (a) após cura da infecção por Lb (n= 23, LCC<3a) e pacientes LCC com até 26 anos de cura da infecção porLb (n= 12, LCC 12-26a). Além disso, 30 isolados de Leishmania de pacientes de leishmaniose cutânea (LC) proveniente da FMT-HVD foram avaliados. Células mononucleares do sangue periférico (CMSP) foram analisadas após estímulo in vitro com antígenos de Lb. A fenotipagem das subpopulações de linfócitos T foi realizada através da citometria de fluxo quanto à ativação, imunosenescência e memória imunológica. A produção de IgG e suas subclasses anti-Leishmania foram avaliadas por ELISA. Os isolados de Leishmania foram caracterizados quanto à espécie pela técnica de isoenzimas...

The main strategy to control American tegumentary leishmaniasis (ATL) isimmunoprophylaxis. To date, no vaccine is available to control spread of the disease. [...] Thus, the purpose of this thesis was to evaluate the evolution of posttreatmentcases of infection with Leishmania naiffi (Ln) and L. braziliensis (Lb) under twodifferent aspects: 1) describe a series of cases of ATL caused by Ln selected from thirtycutaneous leishmaniasis (CL) patients attend at the FMT-HVD, Manaus, in the period 2011-2013. 2) Evaluating the immunological signature, in terms of immunoglobulin subclasses anddifferentiation profile and memory is similar between patients Lb with 26 years of healing aftertreatment with two different treatment regimens with antimony. We studied 43 patients curedcutaneous leishmaniasis (CCL), which are divided into groups: CCL patients followed from theactive phase to three years (y) after cure of Lb infection (n= 23, CCL<3y), CCL patients healedwith up 26 years after infection by Lb (n= 12, CCL 12-26y). In addition, 30 isolates ofLeishmania of patients with cutaneous leishmaniasis (CL) from FMT-HVD were evaluated.Peripheral blood mononuclear cells (PBMC) were analyzed after in vitro stimulation withantigen Lb. The phenotyping of T lymphocyte subpopulations was performed by flow cytometryfor the activation, immunological memory and immunosenescence. The production of IgG andits subclasses anti-Lb were evaluated by ELISA. Isolates of Leishmania were characterized as tospecies by isozyme technique...

Oral bacillus Calmette-Guérin vaccine against tuberculosis: why not?

The bacillus Calmette-Guérin (BCG) vaccine is the only licensed vaccine for human use against tuberculosis (TB). Although controversy exists about its efficacy, the BCG vaccine is able to protect newborns and children against disseminated forms of TB, but fails to protect adults against active forms of TB. In the last few years, interest in the mucosal delivery route for the vaccine has been increasing owing to its increased capacity to induce protective immune responses both in the mucosal and the systemic immune compartments. Here, we show the importance of this route of vaccination in newly developed vaccines, especially for vaccines against TB.

Decreased memory T-cell response and function in human immunodeficiency virus-infected patients with tegumentary leishmaniasis

The effects of human immunodeficiency virus (HIV) on the immune response in patients with cutaneous leishmaniasis have not yet been fully delineated. This study quantified and evaluated the function of memory T-cell subsets in response to soluble Leishmania antigens (SLA) from patients coinfected with HIV and Leishmania with tegumentary leishmaniasis (TL). Eight TL/HIV coinfected subjects and 10 HIV seronegative subjects with TL were evaluated. The proliferative response of CD4+and CD8+T-cells and naïve, central memory (CM) and effector memory (EM) CD4+T-cells in response to SLA were quantified using flow cytometry. The median cell division indices for CD4+and CD8+T-cells of coinfected patients in response to SLA were significantly lower than those in patients with Leishmania monoinfection (p < 0.05). The proportions of CM and EM CD4+T-cells in response to SLA were similar between the coinfected patients and patients with Leishmania monoinfection. However, the median CM and EM CD4+T-cell counts from coinfected patients were significantly lower (p < 0.05). The reduction in the lymphoproliferative response to Leishmania antigens coincides with the decrease in the absolute numbers of both EM and CM CD4+T-cells in response to Leishmania antigens in patients coinfected with HIV/Leishmania.

Involvement of memory T-cells in the pathophysiology of chronic lymphocytic leukemia

The role of T-cells in the pathogenesis of chronic lymphocytic leukemia has recently gained much attention due to the importance of the constant interaction between neoplastic B-cells with microenvironment substratum and T-cells. It is believed that these interactions modulate the clinical course of the disease, mainly through the regulation of the expansion, differentiation, and survival of chronic lymphocytic leukemia B-cells. Importantly, this crosstalk may also change the number, function, and memory phenotype of normal T-cells, thereby altering the amplitude and/or efficiency of adaptive immunity in chronic lymphocytic leukemia patients. The present study presents an overview on important aspects of this immunological crosstalk, particularly on the abnormalities of chronic lymphocytic leukemia B-cells and the alterations in normal T-cells, with focus on the CD4 memory T-cell compartment that could offer survival signals to chronic lymphocytic leukemia B-cell clone(s) and contribute to the establishment and progression of the disease. The authors believe that understanding the biological consequences of the interaction between normal T- and neoplastic B-cells in chronic lymphocytic leukemia may allow for improvements in the prognostic information and therapeutic approaches for this disease.

Avaliação da resposta imunológica após vacinação ou infecção por Neisseria meningitidis / Evaluation of the immune response after vaccination or infection with Neisseria meningitidis

A doença meningocócica (DM) é, ainda hoje, um sério problema de saúde pública, estando associada a elevadas taxas de morbidade e letalidade no mundo. A DM evoca proteção imunológica persistente contra a doença em pessoas com sistema imunológico normal. Em contraste, a proteção induzida por vacinas meningocócicas sempre requer a administração de doses reforço (booster) da vacina. No Brasil, Neisseria meningitidis dos sorogrupos C (MenC) e B (MenB) são as principais causas de DM durante os últimos anos. Atualmente, não existe uma vacina universal contra o meningococo B (MenB). A infecção pelo vírus da imunodeficiência humana (HIV) tem sido apontada como um fator de risco para a mortalidade da DM. Um dos pilares do tratamento do HIV é a utilização de vacinas para doenças imuno-preveníveis. A vacina conjugada anti-MenC é frequentemente recomendada para crianças e adolescentes infectados pelo HIV no Brasil e em muitos outros países. Poucos estudos têm abordado os mecanismos pelos quais as vacinas meningocócicas geram e sustentam a memória imunológica. Os objetivos deste estudo foram: 1) avaliar a resposta de anticorpos bactericidas e de linfócito T (LT) CD4 de memória contra o meningococo após a infecção; 2) avaliar a resposta de anticorpos bactericidas e de LT CD4 de memória e linfócito B de memória (LBm) contra o meningococo após o booster da vacina cubana VA-MENGOC-BC® em voluntários imunizados há aproximadamente 17 anos; 3) investigar a resposta de anticorpos funcionais (bactericidas e opsonizantes) após imunização com a vacina conjugada anti-MenC (CRM197) em indivíduos infectados pelo vírus HIV. Após a infecção, 83% dos pacientes diagnosticados como tendo DM pelo teste de látex e/ou cultura tiveram títulos de anticorpos bactericidas protetores, mas não houve uma associação entre os títulos de anticorpos bactericidas e a concentração de imunoglobulina total específica...

Meningococcal disease (MD) is still a serious public health problem and is associated with high morbidity and mortality rates worldwide. MD evokes persistent immune protection against disease in people with normal immune systems. In contrast, protection induced by meningococcal always requires booster injections of the vaccine. In Brazil, Neisseria meningitidis serogroup C (MenC) and B (MenB) have been the main causes of MD for the past years. Currently, there is no universal vaccine against serogroup B. HIV infection has been implicated as a risk factor for the mortality of meningococcal disease. One of the cornerstones of HIV treatment is the use of vaccines for immunopreventable diseases. The anti-MenC conjugated vaccine is often recommended for children and adolescents infected with HIV in Brazil and many other countries. Few studies have addressed the mechanisms by which meningococcal vaccines generate and sustain immunological memory. The aims of this study were: 1) to evaluate the response of bactericidal antibody and memory CD4 T lymphocyte against meningococcus after infection; 2) to evaluate the bactericidal antibody response and memory T cells and memory B cells against meningococcal booster after the Cuban vaccine VA-MENGOC-BC® in volunteers immunized for about 17 years; 3) to investigate the functional antibody response (bactericidal and opsonizing) after immunization with anti-MenC conjugated vaccine (CRM197) in individuals infected with HIV. After infection, 83% of patients diagnosed as having DM by latex and/or culture test, had protective titers of bactericidal antibodies, but there was no association between the titers of bactericidal antibodies and the total specific immunoglobulin concentration and an increase in frequency of TCM (median of 15%) activated mainly after stimulation with MenC strain...

Short-term and long-term antibody response by mice after immunization against Neisseria meningitidis B or diphtheria toxoid

Serogroup B Neisseria meningitidis (MenB) is a major cause of invasive disease in early childhood worldwide. The only MenB vaccine available in Brazil was produced in Cuba and has shown unsatisfactory efficacy when used to immunize millions of children in Brazil. In the present study, we compared the specific functional antibody responses evoked by the Cuban MenB vaccine with a standard vaccine against diphtheria (DTP: diphtheria, tetanus, pertussis) after primary immunization and boosting of mice. The peak of bactericidal and opsonic antibody titers to MenB and of neutralizing antibodies to diphtheria toxoid (DT) was reached after triple immunization with the MenB vaccine or DTP vaccine, respectively. However, 4 months after immunization, protective DT antibody levels were present in all DTP-vaccinated mice but in only 20% of the mice immunized against MenB. After 6 months of primary immunization, about 70% of animals still had protective neutralizing DT antibodies, but none had significant bactericidal antibodies to MenB. The booster doses of DTP or MenB vaccines produced a significant antibody recall response, suggesting that both vaccines were able to generate and maintain memory B cells during the period studied (6 months post-triple immunization). Therefore, due to the short duration of serological memory induced by the MenB vaccine (VA-MENGOC-BC® vaccine), its use should be restricted to outbreaks of meningococcal disease.

Human dendritic cells sequentially matured with CD4+ T cells as a secondary signal favor CTL and long-term T memory cell responses

Dendritic cells (DCs) are professional antigen-presenting cells involved in the control and initiation of immune responses. In vivo, DCs exposed at the periphery to maturation stimuli migrate to lymph nodes, where they receive secondary signals from CD4+ T helper cells. These DCs become able to initiate CD8+ cytotoxic T lymphocyte (CTL) responses. However, in vitro investigations concerning human monocyte-derived DCs have never focused on their functional properties after such sequential maturation. Here, we studied human DC phenotypes and functions according to this sequential exposure to maturation stimuli. As first signals, we used TNF-α/polyI:C mimicking inflammatory and pathogen stimuli and, as second signals, we compared activated CD4+ T helper cells to a combination of CD40-L/ IFN-γ. Our results show that a sequential activation with activated CD4+ T cells dramatically increased the maturation of DCs in terms of their phenotype and cytokine secretion compared to DCs activated with maturation stimuli delivered simultaneously. Furthermore, this sequential maturation led to the induction of CTL with a long-term effector and central memory phenotypes. Thus, sequential delivery of maturation stimuli, which includes CD4+ T cells, should be considered in the future to improve the induction of long-term CTL memory in DC-based immunotherapy.

Utilização da sílica nanoestruturada SBA-15 como adjuvante em imunizações com a vacina para hepatite B / Nanostructured SBA-15 silica as an adjuvant in immunizations with hepatitis B vaccine

Objective: To evaluate the applicability of SBA-15 silica as an adjuvant in immunizations with purified particles of the viral protein HBsAg, the main component of hepatitis B vaccine, Butang®, produced by Instituto Butantan. Methods: BALB/c mice orally or subcutaneously received 0.5 mug of HBsAg adsorbed/encapsulated to SBA-15 or adsorbed to Al(OH)3. To assess the secondary immune response, a subcutaneous booster was administered 30 days after the first immunization. Individual serum and fecal samples of each group were periodically collected for specific antibody titration by ELISA. Results: Analysis of secretory IgA showed that mice orally primed with HBsAg on SBA-15 had increased levels of specific antibodies in primary and secondary immune responses. Specific serum IgA and IgG titers in HBsAg:SBA-15-orally immunized mice reached higher levels after the booster, demonstrating the effectiveness of oral vaccination with the use of silica. All immunized groups showed higher IgG1 levels. Conclusion: Our results clearly indicate the promising use of SBA-15 as an adjuvant, especially in oral immunizations.

Objetivo: Demonstrar a aplicabilidade da sílica do tipo SBA-15 como adjuvante nas imunizações com a proteína recombinante HBsAg do vírus da hepatite B, principal componente da vacina Butang® produzida pelo Instituto Butantan. Métodos: Camundongos BALB/c receberam, pela via oral ou subcutânea, 0,5 mig do HbsAg adsorvido/encapsulado à SBA-15 ou adsorvido ao Al(OH)3. Para avaliar a resposta imune secundária, uma dose de reforço foi administrada subcutaneamente 30 dias após a primeira imunização. Amostras individuais de soro e fezes foram coletadas periodicamente para titulação de anticorpos específicos por ELISA. Resultados: A análise de IgA secretada mostrou que camundongos imunizados pela via oral com HbsAg em SBA-15 apresentaram aumento nos níveis de anticorpos específicos nas respostas primária e secundária. Ainda, após o reforço, observaram-se maiores níveis de IgA e IgG séricas anti-HBsAg no grupo preparado com HBsAg:SBA-15 pela via oral. Todos os grupos imunizados apresentaram maior produção de IgG1. Conclusão: Os resultados indicam o uso promissor da sílica SBA-15 como adjuvante, especialmente nas imunizações pela via oral.

Immunological correlates of cure in the first American Cutaneous Leishmaniasis patient treated by immunotherapy in Argentina: A case report. / Correlatos inmunológicos de curación en el primer paciente con Leishmaniasis Cutánea Americana tratado con inmunoterapia en Argentina: Reporte de un caso

A patient with localized cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis infection was treated with an antigen containing heat-killed L. (L.) amazonensis promastigotes plus BCG. Expression of T-cell differentiation, memory and senescence receptors markers were analyzed on T cell subpopulations, in order to establish the correlation between the percentages of expression of these receptors and his clinical status, at different stages of his follow up. The following case reports on the achievement of a successful clinical outcome with complete resolution after receiving immunotherapy. A thorough clinical and immunological follow up supporting the healing process of this patient’s lesion is presented in detail.

Un paciente con leishmaniasis cutánea localizada producida por Leishmania (Leishmania) amazonensis fue tratado con un antígeno compuesto por promastigotes de L. (L.) amazonensis muertos por calor combinado con BCG. Se analizó la expresión de distintos receptores de diferenciación, de memoria y de senescencia en las subpoblaciones de células T, con el fin de establecer una relación entre los porcentajes de expresión de dichos receptores y la clínica del paciente en diferentes momentos del seguimiento. Se reporta en este caso un resultado exitoso, con resolución completa de la lesión después de recibir la inmunoterapia, y se presenta en detalle un seguimiento clínico e inmunológico completo durante el proceso de curación.

Desenvolvimento e manutenção de memória imunológica após imunização contra Neisseria meningitidis B com a vacina VA-MENGOC-BC / Development and maintenance of immunological memory after immunization against Neisseria meningitidis B with vaccine VA-MENGOC-BC

Neisseria meningitidis é uma das principais causas de meningite bacteriana e septicemia em todo o mundo, acometendo principalmente crianças menores de 4 anos. Atualmente, não existe uma vacina universal contra o meningococo B (MenB). A imunidade protetora contra o meningococo caracteriza-se pela presença e persistência de anticorpos bactericidas, porém pouco se sabe sobre os mecanismos de desenvolvimento desta memória sorológica. Avaliamos em modelo animal e em humanos, a geração e manutenção das células secretoras de anticorpos (ASC) e dos linfócitos B de memória (LBm) após vacinação contra MenB. Utilizamos como referência a vacina diftérica (dt ou DTP), considerada ter ótima eficácia em humanos. Para o estudo em modelo animal, grupos de 6 a 8 camundongos suíços, fêmeas, de 5 a 6 semanas, foram imunizados com 3 doses da vacina VA-MENGOC-BC ou DTP, via intramuscular, com intervalo de 2 semanas entre as doses. Aproximadamente 2, 4 ou 6 meses após a última dose, os animais receberam a dose reforço. A vacina anti-MenB induziu uma resposta primária de ASC maior que a resposta à dose reforço. Ao contrário, a resposta de ASC à vacina dT foi maior após o booster. A resposta de LBm anti-MenB permaneceu constante (média de 1%) ao longo de todo o estudo, mas a resposta ao toxóide diftérico (TD) foi maior após o booster (média de 1,9%) que após a imunização primária. A concentração de IgC, anticorpos bactericidas e opsonizantes contra MenB foi dose-dependente e foi reativada após a administração das doses reforços. Esses resultados sugerem que os LBm presentes no baço foram responsáveis pela forte resposta de anticorpos observada após a dose reforço. Para o TD, ambas ASC e LBm foram importantes na manutenção da memória sorológica. Para o estudo em humanos, seis voluntários foram imunizados com 3 doses da vacina VA-MENGOC-BC, via intramuscular, com intervalo de 6 a 7 semanas entre as doses. Seis meses após a imunização primária, os indivíduos receberam uma dose...

Neisseria meningitides is one of the leading causes of bacterial meningitis and septicemia worldwide, particularly in children less than four years old. Currently, there is no universal vaccine agoinst serogroup B meningococcus (MenB). Protective immunity against meningococcus is characterized by the presence and persistence of bactericidal antibody, but little is known about the mechanisms of development of the serological memory. In this study, we evaluated in animal model and in humans the generation and maintenance of antibody secreting cells (ASC) and memory B cell after vaccination against MenB. We used the diphtheria vaccine (dT or DTP) as a reference for efficacy in humans. Five to six-week old female Swiss mice in groups of 6 to 8 were immunized with three intramuscular injections of VA-MENGOC-BC or DTP vaccine 2 weeks apart. Approximately 2, 4 or 6 months after the last dose, mice received a booster injection of the vaccine. Vaccination against MenB induced a higher ASC primary response compared with the booster response. In contrast, ASC response to dT was higher after booster than after primary immuinization. Memory B-cell to MenB remained at constant levels (mean of 1%) during the whole study, but the response to diphtheria toxoid (TD) was higher after boosting (mean of 1.9%) when compared with the primary response. IgG, bactericidal and opsonic antibody concentrations to MenB was dose-dependent and was reactivated after booster doses. These data suggest that spleen memory B-cells were responsible for the strong boosting antibody response to MenB. For TD, both ASC and memory B-cell were important for maintenance of the serological memory. For the human study, six volunteers were immunized with three intramuscular injections of VA-MENGOC-BC 6 to 8 weeks apart. Six months after the last dose, subjects received a booster dose. Another group of volunteers (n=5) were immunized with a booster dose of dT vaccine. Three doses of vaccine...

Sistema imunológico: atualidades e perspectivas para a prática clínica / Immune system: present time and perspectives for clinical practice

O sistema imunológico (SI), à semelhança do sistema nervoso, tem uma participação central na biologia do Homo sapiens sapiens (sic), tendo na comunicação um dos esteios para sua organização e funcionamento. Além de ser capaz de distinguir o que é próprio (self) do que é não-próprio (non-self), o SI estrutura-se em rede, processando informações de modo a permitir o aprendizado e o desenvolvimento da memória, aspectos fundamentais para a relação do organismo com o meio ambiente, com importantes implicações no adoecimento humano. Com base nestas considerações, objetiva-se, no presente manuscrito, apresentar, de modo sintético, os principais aspectos do sistema imunológico.

The immune system (IS), like the nervous system, plays a central role in the biology of Homo sapiens sapiens (sic), eith communication as a base for its organization and operation. In addition to an ability to distinguish self from non-self, the IS structures itself in a network, processing information in a way to allow learning and the development of memory, fundamental aspects in the organim's relation with the environment, with important implications in human illnesses. Based on these considerations, this review aims to present, in a synthetic manner, the principal aspects of the immune system.

Imbalance of naive and memory T lymphocytes with sustained high cellular activation during the first year of life from uninfected children born to HIV-1-infected mothers on HAART

The immune consequences of in utero HIV exposure to uninfected children whose mothers were submitted to highly active antiretroviral therapy (HAART) during gestation are not well defined. We evaluated 45 HIV-exposed uninfected (ENI) neonates and 45 healthy unexposed control (CT) neonates. All HIV-infected mothers received HAART during pregnancy, and the viral load at delivery was <50 copies/mL for 56.8 percent. Twenty-three ENI neonates were further evaluated after 12 months and compared to 23 unexposed healthy age-matched infants. Immunophenotyping was performed by flow cytometry in cord and peripheral blood. Cord blood lymphocyte numbers did not differ between groups. However, ENI neonates had a lower percentage of naive T cells than CT neonates (CD4+, 76.6 vs 83.1 percent, P < 0.001; CD8+, 70.9 vs 79.6 percent, P = 0.003) and higher percentages of central memory T cells than CT neonates (CD4+, 13.9 vs 8.7 percent, P < 0.001; CD8+, 8.6 vs 4.8 percent, P = 0.001). CD38 mean fluorescence intensity of T cells was higher in ENI neonates (CD4+, 62.2 vs 52.1, P = 0.007; CD8+, 47.7 vs 35.3, P < 0.001). At 12 months, ENI infants still had higher mean fluorescence intensity of CD38 on T cells (CD4+, 34.2 vs 23.3, P < 0.001; CD8+, 26.8 vs 19.4, P = 0.035). Despite effective maternal virologic control at delivery, HIV-exposed uninfected children were born with lower levels of naive T cells. Immune activation was present at birth and remained until at least 12 months of age, suggesting that in utero exposure to HIV causes subtle immune abnormalities.

Impairment of cytomegalovirus-specific cellular immune response as a risk factor for cytomegalovirus disease in transplant recipients: [review]

Human cytomegalovirus (CMV) infection is common in most people but nearly asymptomatic in immunocompetent individuals. After primary infection the virus persists throughout life in a latent form in a variety of tissues, particularly in precursor cells of the monocytic lineage. CMV reinfection and occurrence of disease are associated with immunosuppressive conditions. Solid organ and bone marrow transplant patients are at high risk for CMV disease as they undergo immunosuppression. Antiviral treatment is effective in controlling viremia, but 10-15 percent of infected patients can experience CMV disease by the time the drug is withdrawn. In addition, long-term antiviral treatment leads to bone marrow ablation and renal toxicity. Furthermore, control of chronic CMV infection in transplant recipients appears to be dependent on the proper recovery of cellular immunity. Recent advances in the characterization of T-cell functions and identification of distinct functional signatures of T-cell viral responses have opened new perspectives for monitoring transplant individuals at risk of developing CMV disease.

Estudo da ativação e da resposta aos antígenos de memória em indivíduos infectados pelo HTLV-1 / Study of the activation and the reply to antigens of memory in individuals infected for the HTLV-1

(...)vírus linfotrópico de células T humanas do tipo 1(HTLV-1)tem tropismo para os linfócitos T,infectando preferencialmente linfócitos T CD4+CD45RO+,embora outras células possam ser alvo da infecção.No Brasil,a prevalência em doadores de sangue foi estimada em 0,45por cento,sendo Salvador o epicentro da infecção do HTLV-1 no país,com prevalência de 1,35por cento.Recentemente,um estudo de base populacional,realizado em Salvador revelou uma prevalência de 2por cento.O HTLV-1 está classicamente associado a leucemia e linfoma de células T do adulto (ATLL),Paraparesia espástica tropical/mielopatia associada ao HTLV-1(HAM/TSP)e uveite.Este vírus também está relacionado a outras doenças inflamatórias como artrite,dermatite infectiva,polimiosite,alveolite e Síndrome de Sjõgren.A infecção pelo HTLV-1,induz uma ativação crônica do sistema imune e uma maior susceptibilidade a doenças infecciosas.Maior morbidade e mortalidade associada à tuberculose,hanseníase, estrongiloidíase grave e disseminada,e escabiose severa sugerem a existência de uma imunossupressão pelo HTLV-1. Células...Neste estudo...CD4+CD45RO+,nos indivíduos infectados com proliferação espontânea e uma menor frequência de resposta aos antígenos de memória, mesmo nos indivíduos cujos PBMC não proliferavam espontaneamente.Além disso,indivíduos com proliferação espontânea apresentaram expansão policlonal dos linfócitos T CD4+.Em seguida,investigamos o perfil de ativação e a freqüência de células produtoras de IFN-γ.A expressão de CD25,CD69 e HLA-DR,bem como a proporção de células produtoras de IFN-γ foi maior nos linfócitos T CD4+ dos indivíduos infectados pelo HTLV-1.Por fim,investigamos o potencial inibitório de compostos quinolínicos na proliferação espontânea de linfócitos T, de indivíduos infectados pelo HTLV-1.Identificamos 6 compostos(XF907,XF731,SF103,MHM22,MDS14 and SF47)com capacidade para inibir,in vitro,a proliferação espontânea de PBMC.Novos estudos para avaliar o mecanismo de inibição...

Características morfológicas de huella vacunal del BCG en estudiantes de medicina / Characterization of the vaccination print with the BCG, administered at birth in students of Medicine

Con el objetivo de conocer la caracterización cuali-cuantitativa de la huella de la vacunación con el BCG administrada al nacimiento, como indicador de potencialidades inmunológicas de forma temporal o permanente, hemos realizado un trabajo en estudiantes de Medicina, de edades entre 18 y 20 años, Se identificó presencia o no de huella y se midieron los diámetros transversales y longitudinales de las lesiones residuales, y se informó el promedio de ambas lecturas. A un subgrupo, se le realizó cuantificación de anticuerpos anti HBs mediante método inmunoenzimático, después de dosis de refuerzo de 20 μgvacuna de hepatitis B. En 103 de 123 (83,7(por ciento) de los estudiantes que habían recibido el BCG, se logró identificar huella de la vacuna, con un diámetro promedio de7,74mm, DS de 3,85 y CV de 49,7(por ciento) Los factores inmunológicos que justifican la huella de la vacuna aplicada en condiciones standard y de buenas prácticas, tienen una base genética que es totalmente individual, que demuestra la gran desviación standard observada. En el grupo al que se cuantificó, anti HBs, todos tenían respuesta al BCG, y tuvieron también, una magnífica respuesta de memoria inmunológica al HBsAg (987±240 UI/L promedio). Nos proponemos, como parte de un proyecto de investigación de nuestro Centro, realizar estudios prospectivos a niños de diferentes edades; y donde no aparezca huella del BCG, estudiar respuesta inmune para otras vacunas del PAI