Persistence follow-up of immune memory to hepatitis B vaccine among infants with non- and low-response to primary vaccination after revaccination with three doses / 中华预防医学杂志

This study followed up the immune memory after 3-dose revaccination among infants with non-and low-response following primary hepatitis B (HepB) vaccination. About 120 children without self-booster doses were finally included who had anti-HBs<10 mIU/ml (anti-HBs negative) at the time of follow-up, of whom 86 children completed blood sampling and anti-HBs testing. Before the challenge dose, all 86 children were negative for anti-HBs, and the GMC of anti-HBs was<10 mIU/ml. The seropositive conversion rate of anti-HBs was 100% and the GMC of anti-HBs was 886.11 (95%CI: 678.15-1 157.84) mIU/ml after the challenge dose. Compared with those with GMC<7 mIU/ml before the challenge dose, infants with GMC>7 mIU/ml had a higher anti-HBs level after the challenge dose. The β value (95%CI) was 0.82 (0.18-1.46) (P=0.012). Compared with those with GMC<1 000 mIU/ml at primary vaccination, infants with GMC≥1 000 mIU/ml had a higher anti-HBs level after the challenge dose. The β value (95%CI) was 0.78 (0.18-1.38)(P=0.012). The results showed a stronger immune memory was found at 9 years after revaccination among infants with non-and low-response to HepB.

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.

Metabolic Reprogramming by the Excessive AMPK Activation Exacerbates Antigen-Specific Memory CD8⁺ T Cell Differentiation after Acute Lymphocytic Choriomeningitis Virus Infection

During virus infection, T cells must be adapted to activation and lineage differentiation states via metabolic reprogramming. Whereas effector CD8⁺ T cells preferentially use glycolysis for their rapid proliferation, memory CD8⁺ T cells utilize oxidative phosphorylation for their homeostatic maintenance. Particularly, enhanced AMP-activated protein kinase (AMPK) activity promotes the memory T cell response through different pathways. However, the level of AMPK activation required for optimal memory T cell differentiation remains unclear. A new metformin derivative, IM156, formerly known as HL156A, has been reported to ameliorate various types of fibrosis and inhibit in vitro and in vivo tumors by inducing AMPK activation more potently than metformin. Here, we evaluated the in vivo effects of IM156 on antigen-specific CD8⁺ T cells during their effector and memory differentiation after acute lymphocytic choriomeningitis virus infection. Unexpectedly, our results showed that in vivo treatment of IM156 exacerbated the memory differentiation of virus-specific CD8⁺ T cells, resulting in an increase in short-lived effector cells but decrease in memory precursor effector cells. Thus, IM156 treatment impaired the function of virus-specific memory CD8⁺ T cells, indicating that excessive AMPK activation weakens memory T cell differentiation, thereby suppressing recall immune responses. This study suggests that metabolic reprogramming of antigen-specific CD8⁺ T cells by regulating the AMPK pathway should be carefully performed and managed to improve the efficacy of T cell vaccine.

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.

MicroRNA-mediated Regulation of the Development and Functions of Follicular Helper T cells

The germinal center reaction is a key event of humoral immunity, providing long-lived immunological memory. Follicular helper T (T(FH)) cells are a specialized subset of CD4⁺ T cells located in the follicles, which help B cells and thus control the germinal center reaction. T(FH) cell development is achieved by multi-step processes of interactions with dendritic cells and B cells along with the coordination of various transcription factors. Since the T helper cell fate decision program is determined by subtle changes in regulatory molecules, fine tuning of these dynamic interactions is crucial for the generation functional T(FH) cells. MicroRNAs (miRNAs) have emerged as important post-transcriptional regulatory molecules for gene expression, which consequently modulate diverse biological functions. In the last decade, the miRNA-mediated regulation network for the germinal center reaction has been extensively explored in T cells and B cells, resulting in the identification of several key miRNA species and their target genes. Here, we review the current knowledge of the miRNA-mediated control of the germinal center reaction, focusing on the aspect of T cell regulation in particular. In addition, we highlight the most important issues related to defining the functional target genes of the relevant miRNAs. We believe that the studies that uncover the miRNA-mediated regulatory axis of T(FH) cell generation and functions by defining their functional target genes might provide additional opportunities to understand germinal center reactions.

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.

Assessment of immunological markers and booster effects of Ag85B peptides, Ag85B, and BCG in blood of BCG vaccinated children: a preliminary report

PURPOSE: In the present study, the protective immunological markers in serum and peripheral blood mononuclear cells (PBMCs) of bacillus Calmette-Guerin (BCG) vaccinated and unvaccinated children were evaluated after vaccination. Further, PBMCs of children with low protective levels were boosted with BCG, Ag85B, and Ag85B peptides to study their booster effects to increase waning BCG induced immunity. MATERIALS AND METHODS: Fifty children from 1 month to 18 years of age were randomized for the study. Blood samples were collected from 27 participants with/without BCG vaccination. Immunological markers (anti-BCG, interferon gamma [IFN-gamma], and adenosine deaminase activity) were assessed in both serum and PBMCs of children. Children with low levels of protective immunological markers were further recruited and their PBMCs were boosted with BCG, Ag85B, and Ag85B peptides. RESULTS: Children in age group of 4-6 years were associated with significantly (p<0.05) higher BCG-specific IgG and IFN-gamma levels compared to those in age group greater than 10 years. Vaccinated children had greater repertoire of immunological memory which on in vitro stimulation with BCG showed increase in BCG-specific response compared to unvaccinated controls. Assessment of booster effects of BCG, Ag85B, and Ag85B peptides in PBMCs of children revealed greater potential of peptides to boost BCG induced immunity compared to BCG and Ag85B. CONCLUSION: To conclude, children within age 4-6 years are associated with high immunological markers which eventually diminish with age thereby suggesting need for booster dose in later years. Mycobacterium tuberculosis peptides along with BCG may be used as attractive candidates to boost such waning BCG induced immunity in children.

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...

Persistence of immune memory to hepatitis B vaccine among infants with normal or high antibody response to primary vaccination: a five-year following-up study / 中华流行病学杂志

<p><b>OBJECTIVE</b>To examine the immune memory status to hepatitis B vaccine among infants with normal or high antibody response to primary vaccination, 5 years after the primary vaccination and the risk factors associated with the immune memory.</p><p><b>METHODS</b>Titers of the antibody against hepatitis B surface antigen (anti-HBs) were detected, five years after the primary vaccination among children who appeared normal or high response to hepatitis B primary vaccination in infancy. Those whose anti-HBs titers were low than protective level (10 mIU/ml) were given a challenge dose of hepatitis B vaccine and titers of anti-HBs were detected 14 days after the challenge. Positive rate and geometric mean titer (GMT) of anti-HBs were calculated. Level of the anti-HBs titers after primary vaccination, at following-up and after the challenge periods were divided into different levels, respectively. Risk factors associated with the levels of anti-HBs titer after the challenge were examined by univariate analysis that and multivariable analysis.</p><p><b>RESULTS</b>Anti-HBs waned to the level below protective standard among 37.98% of the children with normal or high antibody response to hepatitis B primary vaccination; among those children whose anti-HBs were below the protection standard. The seroconversion rate and GMT of anti-HBs after the challenge dose were 98.95% (757/765) and 2 811.69 mIU/ml [95% Confidence Interval (CI) :2 513.55-3 145.19 mIU/ml] , respectively. Titers and levels of anti-HBs after the challenge, appeared an increase with anti-HBs after primary vaccination and the anti-HBs in the following-up (F=5.46, 10.23 respectively; P<0.000 1 for both) periods. Results from the multivariable analysis showed that gender, premature birth and birth weight were factors insignificantly associated with the anti-HBs titers after the dose of challenge, while the anti-HBs levels were independently associated with the levels of anti-HBs titer after the challenge [OR = 1.001 (95%CI: 1.000-1.002) , P<0.001; OR=1.28 (95%CI: 1.81-1.39) , P<0.001]at the following-up periods.</p><p><b>CONCLUSIONS</b>Strong immune memory could be found among those children with normal or high responses to hepatitis B vaccination, 5 years after the primary vaccination. The intensity of immune memory might be associated with the anti-HBs titer after primary vaccination as well as the anti-HBs titers before the challenge dose was given.</p>

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...

Memory B (CD5⁺ CD19⁺ CD27⁺) lymphocyte in patients with immune-related pancytopenia / 中华血液学杂志

<p><b>OBJECTIVE</b>To detect memory B lymphocyte (Bm) in peripheral blood (PB) of immune-related pancytopenia (IRP).</p><p><b>METHODS</b>86 patients with IRP and 11 health volunteers were enrolled in this study. Bm (CD5⁺ CD19⁺ CD27⁺) and bone marrow mononucleated cell antibodies (BMMNC-Ab) were determined via fluorescence-activated cell sorting, and clinical outcomes of these patients were analyzed.</p><p><b>RESULTS</b>(1)43 initial patients achieved obvious remission in all 52 initial cases after conventional immunosuppression therapy. 16 relapsed patients with IRP received Rituximab (RTX) and 14 cases achieved obvious remission, among which 7 cases were refractory to conventional immunosuppression therapy, 5 cases exhibited obvious remission, and 2 cases did not respond. Other 18 relapsed cases received conventional immunosuppression therapy and 13 cases achieved obvious remission. (1)The level of Bm in PB in 52 initial patients with IRP was(1.81 ± 0.97)%, and no significant difference was observed between the initial patients and health volunteers (1.75 ± 0.55)% (P>0.05). The level of Bm in PB in 34 relapsed patients with IRP was obviously higher than that in the initial IRP patients and health volunteers (P<0.05). Significant difference was observed in the level of Bm in PB in 16 relapsed IRP patients between pre-therapy and post-therapy with RTX (P<0.05). No statistical difference was found between the remission and no-response groups in relapsed patients treated with RTX. RTX regimen produced more effective outcome than conventional immunosuppression therapy, which better eliminated Bm than the latter (P<0.05). Initial patients with IRP who relapsed within a two-year follow-up period had a lower level of Bm in PB compared with un-relapsed patients (P<0.05). Majority of BMMNC- Ab antibodies in relapsed patients were IgG (82.4%) and IgM (69.2%) autoantibodies in patients with initial IRP.</p><p><b>CONCLUSION</b>The level of Bm in PB was associated with relapsed patients with IRP. Bm did not respond to conventional immunosuppression therapy,but responded to RTX.</p>

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.

A cross-sectional study on the effect of virological response after HAART on subsets of T lymphocytes and expression of CD127 in pediatric AIDS patients with different viral loads / 中华儿科杂志

<p><b>OBJECTIVES</b>To study the effect of HAART on subsets of T lymphocytes and expression of CD127 on memory and naїve CD4(+) and CD8(+)T cells in pediatric AIDS patients with different viral loads receiving HAART.</p><p><b>METHOD</b>A cross- sectional study on 194 pediatric AIDS patients receiving HAART was carried out and 52 age matched healthy children were recruited as controls. The percentage of CD4(+), CD8(+), CD8(+)CD45RA(+)CD127(+/-), CD8(+)CD45RO(+)CD127(+/-), CD4(+)CD45RA(+)CD127(+/-) and CD4(+)CD45RO(+)CD127(+/-)T cells was tested using flow cytometry, and HIV-RNA in plasma was detected by quantitative RT-PCR.</p><p><b>RESULT</b>The percentage of memory (CD45RO(+)) CD4(+)T cells decreased to (45.73 ± 8.85)%, and that of naїve (CD45RA(+)) CD4(+) and memory CD8(+)T increased to (60.44 ± 5.01)% and (54.69 ± 7.71) % respectively in the pediatric AIDS patients vs. controls (P < 0.05). The percentage of naїve (CD45RA(+)) CD4(+)T cells of patients with viral load (VL) < 400 copies/ml was (65.57 ± 5.33) %, which was significantly higher than that of patients with VL ≥ 400 copies/ml (P < 0.05).Of patients with VL < 400 copies/ml, the percentage of CD4(+)CD127(+)T cells, especially the subset of memory CD4(+)CD127(+)T cells was (82.35 ± 2.31)%, which was higher than that of patients with VL ≥ 400 copies/ml, but lower than that of controls (P < 0.05). The percentage of memory and naїve CD8(+)CD127(+)T cells was lower than that of controls (P < 0.05).</p><p><b>CONCLUSION</b>The recovery of CD4(+)T cell subsets in pediatric AIDS patients is associated with viral load. Effective HAART can increase the percentage of naїve CD4(+)T cells and the life of memory CD4(+)T cells.</p>

High frequency of regulatory T cells among HIV type 1-infected men who have sex with men correlates with disease progression / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Regulatory T cells (Tregs) may play an important role in immunopathology during HIV-1 infection. Transcription factor forkhead box P3 (FoxP3) orchestrates the development of Tregs and is a useful marker to identify this population. Using a FoxP3 phenotype to define Tregs, we investigated the level and phenotype of peripheral blood natural CD4(+)Tregs and assessed the relationship between the frequencies and absolute numbers of CD4(+) Tregs and disease progression among untreated HIV-infected men who have sex with men (HIV(+) MSM) in China.</p><p><b>METHODS</b>Fifty-two untreated HIV(+) MSM with CD4(+) T-cell counts of ≤ 350 cells/µl or > 350 cells/µl were compared in a cross-sectional study. Twelve age-matched HIV-uninfected MSM and nine patients receiving antiretroviral therapy for at least 1 year were also included. Expression of CD25, CD127, CD45RA, CCR7 and CTLA-4 was assessed on CD4(+) Tregs using polychromatic flow cytometry.</p><p><b>RESULTS</b>The percentage of CD4(+) Tregs was increased significantly, whereas CD4(+) Tregs expressed less CTLA-4 in HIV(+) MSM compared with controls. CD4(+) Tregs displayed predominantly an effector memory phenotype (CD45RA(-) CCR7(-)), phenotypically distinct from conventional CD4(+) T cells. Moreover, the expansive frequencies of CD4(+) Tregs coincided with lower CD4(+) T-cell counts and higher viral loads whereas the absolute numbers of CD4(+) Tregs were associated with higher CD4(+) T-cell counts and lower viral loads. The expansion of Tregs was also associated with CD8(+) T-cell activation.</p><p><b>CONCLUSION</b>Increased proportions and decreased numbers of CD4(+) Tregs are associated with HIV progression, and their functions may impair with the progression of HIV infection.</p>

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.