The Spleen CD4+ T Cell Response to Blood-Stage Plasmodium chabaudi Malaria Develops in Two Phases Characterized by Different Properties

The pivotal role of spleen CD4+ T cells in the development of both malaria pathogenesis and protective immunity makes necessary a profound comprehension of the mechanisms involved in their activation and regulation during Plasmodium infection. Herein, we examined in detail the behaviour of non-conventional and conventional splenic CD4+ T cells during P. chabaudi malaria. We took advantage of the fact that a great proportion of CD4+ T cells generated in CD1d-/- mice are I-Ab-restricted (conventional cells), while their counterparts in I-Ab-/- mice are restricted by CD1d and other class IB major histocompatibility complex (MHC) molecules (non-conventional cells). We found that conventional CD4+ T cells are the main protagonists of the immune response to infection, which develops in two consecutive phases concomitant with acute and chronic parasitaemias. The early phase of the conventional CD4+ T cell response is intense and short lasting, rapidly providing large amounts of proinflammatory cytokines and helping follicular and marginal zone B cells to secrete polyclonal immunoglobulin. Both TNF-α and IFN-γ production depend mostly on conventional CD4+ T cells. IFN-γ is produced simultaneously by non-conventional and conventional CD4+ T cells. The early phase of the response finishes after a week of infection, with the elimination of a large proportion of CD4+ T cells, which then gives opportunity to the development of acquired immunity. Unexpectedly, the major contribution of CD1d-restricted CD4+ T cells occurs at the beginning of the second phase of the response, but not earlier, helping both IFN-γ and parasite-specific antibody production. We concluded that conventional CD4+ T cells have a central role from the onset of P. chabaudi malaria, acting in parallel with non-conventional CD4+ T cells as a link between innate and acquired immunity. This study contributes to the understanding of malaria immunology and opens a perspective for future studies designed to decipher the molecular mechanisms behind immune responses to Plasmodium infection

Anti-IL-2 Treatment Impairs the Expansion of Treg Cell Population during Acute Malaria and Enhances the Th1 Cell Response at the Chronic Disease

Plasmodium chabaudi infection induces a rapid and intense splenic CD4+ T cell response that contributes to both disease pathogenesis and the control of acute parasitemia. The subsequent development of clinical immunity to disease occurs concomitantly with the persistence of low levels of chronic parasitemia. The suppressive activity of regulatory T (Treg) cells has been implicated in both development of clinical immunity and parasite persistence. To evaluate whether IL-2 is required to induce and to sustain the suppressive activity of Treg cells in malaria, we examined in detail the effects of anti-IL-2 treatment with JES6-1 monoclonal antibody (mAb) on the splenic CD4+ T cell response during acute and chronic P. chabaudi AS infection in C57BL/6 mice. JES6-1 treatment on days 0, 2 and 4 of infection partially inhibits the expansion of the CD4+CD25+Foxp3+ cell population during acute malaria. Despite the concomitant secretion of IL-2 and expression of high affinity IL-2 receptor by large CD4+ T cells, JES6-1 treatment does not impair effector CD4+ T cell activation and IFN-γ production. However, at the chronic phase of the disease, an enhancement of cellular and humoral responses occurs in JES6-1-treated mice, with increased production of TNF-α and parasite-specific IgG2a antibodies. Furthermore, JES6-1 mAb completely blocked the in vitro proliferation of CD4+ T cells from non-treated chronic mice, while it further increased the response of CD4+ T cells from JES6-1-treated chronic mice. We conclude that JES6-1 treatment impairs the expansion of Treg cell population during early P. chabaudi malaria and enhances the Th1 cell response in the late phase of the disease

Influenza seroprotection correlates with predominant circulating viruses during 2014/15 and 2015/16 seasons in Portugal

Rede Portuguesa de Laboratórios para o Diagnóstico da GripeBACKGROUND: Population immune profile for influenza is highly affected by circulating influenza viruses, thus changing the risk of infection for influenza. This study aims to assess influenza immunity in the Portuguese population by age groups, during 2014 and 2015 and establish a relationship between seroprotection and circulating influenza viruses in 2014/15 and 2015/16 seasons. METHODS: Two cross-sectional studies were developed based on a convenience serum sample collected in June 2014 (n=626) and July 2015 (n=675) in hospitals from mainland and Azores and Madeira.Serums equally represent all age groups. Antibody titers were evaluated by HI assay for strains recommended for seasonal influenza vaccine northern hemisphere,2014/15 and 2015/2016. Seroprevalences were estimated for each strain by age group and the association with seasonal cumulative influenza-like illness (ILI) rates for influenza virus during both seasons was analised. RESULTS: In June 2014 the highest seroprotection was observed for influenza A(H3) (39.0%; 95% CI: 36.2-43.8%) and A(H1)pdm09 (29.7; 95% CI: 26.3-33.4%), with higher levels in children 5-14 years old. In 2014/2015 a dominant circulation of influenza B/Yamagata was observed with high incidence rates in individuals under 65 years old, the ones that had lower seroprotection. Although before the start of the season high protection for A(H3) was observed, the circulation of the new drift A(H3) strains had gained an immunological advantage,in accordance with A(H3) elevated incidence rates observed during 2014/15. In July 2015 the highest seroprotection was observed for influenza B/ Yamagata (55.1%; 95% CI: 51.4-58.9%), 2.4 times the estimated 2014.This increase was even more pronounced in younger (≤ 4 years old), 6.3 times increase in 2015.This fact is in agreement with the predominant influenza B virus detected and the high ILI incidence rate observed in children during 2014/2015 epidemic. Seroprotection levels for influenza A in July 2015 were not significantly different from 2014.During 2015/16 season, influenza A(H1N1)pdm09 was predominant, with high incidence rate in < 65 year old. Influenza B/Victoria lineage,although detected at low levels increased in frequency, in agreement with the lowest level of seroprotection detected in the general population before the start of 2015/2016 season (21.8%; 95% CI: 18.7-24.0%). CONCLUSIONS There was a correlation between virus circulation, incidence rates for each age group and the previous seroprotection for seasonal influenza viruses.Our study highlights the value of measuring the serological profile for influenza to establishe risk groups for infection for which an increase preventive measures, including vaccination, should be fostered.info:eu-repo/semantics/publishedVersio

Influenza severe cases in hospitals, between 2014 and 2016 in Portugal

Rede Portuguesa de Laboratórios para o Diagnóstico da GripeBackground: Since 2009, the Portuguese Laboratory Network (PLNID) for Influenza Diagnosis has integrated 15 Laboratories in mainland and Atlantic Islands of Azores and Madeira. This PLNID added an important contribute to the National Influenza Surveillance Program regarding severe and hospitalized influenza cases. The present study aims to describe influenza viruses detected in influenza like illness (ILI) cases: outpatients (Outp), hospitalized (Hosp), and intensive care units (ICU), between 2014 and 2016. Methods: The PLNID performs influenza virus diagnosis by biomolecular methodologies. Weekly reports to the National Influenza Reference Laboratory ILI cases tested for influenza. Reports include data on detecting viruses, hospital assistance, antiviral therapeutics, and information on death outcome. Were reported during two winter seasons 8059 ILI cases,being 3560 cases in 2014/15 (1024 in Outp, 1750 Hosp, and 606 in ICU) and 4499 cases in 2015/2016 (1933 in Outp, 1826 Hosp, and 740 in ICU). Results: The higher percentage of influenza positive cases were detected in Outp in both seasons, 18% during 2014/15 and 20% in 2015/16. In 2014/15,influenza cases were more frequent in individuals older than 65 years old and these required more hospitalizations,even in ICU. In 2015/16,the influenza cases were mainly detected in individuals between 15-64 years old. A higher proportion of influenza positive cases with hospitalization in ICU were observed in adults between 45-64 years old.During the study period,the predominant circulating influenza viruses were different in the two seasons: influenza B and A(H3) co-circulated in 2014/15,and influenza A(H1)pdm09 was predominant during 2015/16. Even when influenza A is notthe dominant virus, A(H3) and A(H1)pdm09 subtypes correlate with higher detection rate in hospitalized cases (Hosp and UCI), with higher frequencies in adults older than 45. Influenza B,detected in higher proportion in outpatients, was frequently relatedwith influenza cases in younger age groups: 0-4 and 5-14 years old. Conclusions: This study highlights the correlation of theinfluenza virus type/subtype that circulates in each season with the possible need for hospitalization and intensive care in special groups of the population. Circulation of influenza A subtypes can cause more frequentdisease in individuals older than 45, with need of hospitalization including intensive care. On the other hand, influenza B is more frequently associated with less severe cases and with infection in children and younger adults. Influenza B circulation might predict lower number of hospitalizations.The identification of influenza type in circulation,byPLNID ineach season, could guide action planning measures in population health care.info:eu-repo/semantics/publishedVersio

Avaliação do sobrepeso e obesidade infantil em alunos do 5º ano do ensino fundamental de escolas municipais e particulares de Foz do Iguaçu - Paraná: Assessment of children’s weight levels and obesity in 5th year elementary school students from public and private schools in Foz do Iguaçu - Paraná

A obesidade na infância é decorrente de vários fatores, sendo que o sedentarismo e os erros alimentares estão entre as principais causas da obesidade infantil, podendo exercer grande influência sobre a predisposição genética. O objetivo deste trabalho foi identificar as possíveis diferenças nos valores de sobrepeso e obesidade entre os alunos do 5º ano de escolas municipais e particulares de Foz do Iguaçu/PR, bem como os níveis de colesterol e glicemia. As avaliações antropométricas foram conduzidas por meio de medidas do índice de massa corpórea (IMC), enquanto que os níveis de glicose e colesterol foram avaliados por meio do uso de medidores portáteis que utilizam uma amostra capilar (dedo).  A pesquisa foi realizada em 449 alunos, sendo 92 crianças oriundas de escolas particulares e 357 da rede municipal de ensino. Os resultados obtidos para sobrepeso/obesidade não se mostraram estatisticamente diferentes entre as escolas particulares e municipais (p=0,648). No entanto, a análise de variância dos níveis de glicemia das crianças estudadas, permitiu estabelecer uma associação entre os resultados desta variável com o nível socioeconômico, com p inferior a 0,0001, com os resultados mais elevados para a rede municipal. A avaliação dos níveis de colesterol demonstrou uma correlação oposta ao observado para a glicemia, onde os valores médios registrados foram maiores para as escolas particulares, com p igual a 0,0023. A prevalência observada nos níveis mais elevados de colesterol total nos alunos de escolas particulares em relação às escolas públicas, pode estar relacionada com perfis diferentes de atividade física/sedentarismo nas diferentes populações estudadas.A obesidade na infância é decorrente de vários fatores, sendo que o sedentarismo e os erros alimentares estão entre as principais causas da obesidade infantil, podendo exercer grande influência sobre a predisposição genética. O objetivo deste trabalho foi identificar as possíveis diferenças nos valores de sobrepeso e obesidade entre os alunos do 5º ano de escolas municipais e particulares de Foz do Iguaçu/PR, bem como os níveis de colesterol e glicemia. As avaliações antropométricas foram conduzidas por meio de medidas do índice de massa corpórea (IMC), enquanto que os níveis de glicose e colesterol foram avaliados por meio do uso de medidores portáteis que utilizam uma amostra capilar (dedo).&nbsp; A pesquisa foi realizada em 449 alunos, sendo 92 crianças oriundas de escolas particulares e 357 da rede municipal de ensino. Os resultados obtidos para sobrepeso/obesidade não se mostraram estatisticamente diferentes entre as escolas particulares e municipais (p=0,648). No entanto, a análise de variância dos níveis de glicemia das crianças estudadas, permitiu estabelecer uma associação entre os resultados desta variável com o nível socioeconômico, com p inferior a 0,0001, com os resultados mais elevados para a rede municipal. A avaliação dos níveis de colesterol demonstrou uma correlação oposta ao observado para a glicemia, onde os valores médios registrados foram maiores para as escolas particulares, com p igual a 0,0023. A prevalência observada nos níveis mais elevados de colesterol total nos alunos de escolas particulares em relação às escolas públicas, pode estar relacionada com perfis diferentes de atividade física/sedentarismo nas diferentes populações estudadas

Analysis of T-and B-cell memory after untreated and drug treated blood-stage Plasmodium chabaudi AS malaria.

A exposição limitada ao Plasmodium chabaudi induz proeminente imunidade celular, associada à proteção de células T da apoptose. Este estudo tem como objetivo verificar a influência da carga parasitária na geração e manutenção dos linfócitos T e B de memória ao P. chabaudi. Assim, camundongos C57BL/6 foram submetidos à infecção tratada (subpatente) ou não (patente) com cloroquina após a inoculação de 106 eritrócitos parasitados (EP) e analisados nos dias 0, 20, 60, 120 e 200. Com relação à memória de linfócitos T, no dia 20, as freqüências de células CD4+ memória/ativadas e respondedoras aos EP foram significativamente maiores nos animais do grupo subpatente. Os níveis máximos de IgG2a específica foram encontrados no dia 120 em ambos os grupos. O desafio dos animais com 108 EP mostrou que a imunidade protetora declina progressivamente, mas os grupos ainda são capazes de estabelecer resposta secundária eficiente que elimine o parasita. Assim, podemos concluir que a carga parasitária influencia a fase aguda, mas não impede a geração e manutenção das células T e B de memória.One of the main characteristics of malaria is the intense policlonal activation of splenic T and B lymphocytes induced by the parasite and the consequent elimination, through apoptosis, of part of these cells. However, the limited exposure to the bloodstage malaria seems to induce a prominent cellular immunity, associated with the protection of T lymphocytes from apoptosis. With this in mind, this study aimed to verify the influence of the parasite load in the generation and maintenance of memory T and B cells specific for Plasmodium chabaudi chabaudi AS. In order to evaluate this idea, C57BL/6 mice were infected with 106 parasitized red blood cells (pRBC) and submitted to a patent (untreated) or subpatent infection (controlled with sub-curative doses of chloroquine every time parasitemia reached 1%). Splenocytes from these mice were analyzed at 20, 60, 120 and 200 days after infection, regarding the pRBC-specific T cell proliferation and the expression of surface molecules, as CD4, CD8, CD62L, CD45RB, CD44, CD45R-B220 and IgG. The parasitemia and the splenocyte phenotype were also monitored after the challenge with 108 pRBC. Regarding T cell memory, at day 20 of infection, the frequencies of effector/activated CD4+ T cells (CD62LLOW CD45RBLOW/HIGH) were significantly increased in animals from the patent group, which was strict linked with the highest cellular activation observed in these animals. On the other hand, the total numbers of pRBCproliferating T (CD4+ and CD8+) cells per spleen were approximately 3-fold increased in subpatent animals, indicating that these cells were protected from apoptosis as a result of the limited exposure to the parasite. However, in both groups, these parameters decreased to values similar to those in controls at day 200. The splenocytes from both groups produced Th1 cytokines in response to pRBC in all times of analysis, but at the early phase of infection, Th2 cytokines were also observed, but without differences between the infected groups. Regarding memory B cells, the frequency of sIgG+ cells was increased at day 20 of infection, when 11% and 9% of CD45R+ cells from patent and subpatent animals were positive, respectively. For both groups, specific IgG2a antibodies attained maximum serum levels at day 120, but at day 200, it is possible to observe a significant decrease of these levels only in the serum of patent mice. Moreover, at day 200 of infection, mice of subpatent group showed significantly higher amounts of IgG2a that recognized the intra-erythrocytic forms of the parasite and the surface of infected erythrocytes. Challenge of mice with 108 pRBC showed that protective immunity progressively decline with time and despite the higher levels of specific antibody in subpatent mice, both groups showed similar protection. In experiments of adoptive transference to CD28-/- mice, cells from 200-day infected mice were able to produce specific IgG2a antibodies, in a T CD4+ cell dependent way. In addition, we verified that CD45R+ cells of subpatent mice, when transferred to CD28-/- mice, secreted higher amounts of specific IgG2a and IgG1 antibodies, comparing to cells of patent mice. So, from this work, we can conclude that the parasite load has a great influence in the early immune response to P. chabaudi malaria and it also affects the generation and/or maintenance of memory B cells. Furthermore, according to our data, at least during the analyzed period, the loss of protective immunity against this parasite does not seem to be influenced by the acute-phase parasite load, but it can be a consequence of the progressive decline of T-cell memory response that occurs in patent and subpatent groups with time of infection

IL-27 promotes IL-10 production by effector Th1 CD4 +T cells: A critical mechanism for protection from severe immunopathology during malaria infection

Infection with the malaria parasite, Plasmodium, is characterized by excessive inflammation. The establishment of a precise balance between the pro- and anti-inflammatory responses is critical to guarantee control of the parasite and survival of the host. Interleukin (IL)-10, a key regulatory cytokine produced by many cells of the immune system, has been shown to protect mice against pathology during acute Plasmodium chabaudi chabaudi AS model of malaria. However, the critical cellular source of IL-10 is still unknown. Here, we demonstrate that T cell-derived IL-10 is necessary for the control of pathology during acute malaria, as mice bearing specific deletion of Il10 in T cells fully reproduce the phenotype observed in Il10(−/−) mice, with significant weight loss, drop in temperature and increased mortality. Furthermore, we show that IFN-γ(+) Th1 cells are the main producers of IL-10 throughout acute infection, expressing high levels of CD44 and ICOS and low levels of CD127. Although Foxp3(+) regulatory CD4(+) T cells produce IL-10 during infection, highly activated IFN-γ(+) Th1 cells were shown to be the essential and sufficient source of IL-10 to guarantee protection against severe immune-mediated pathology. Finally, in this model of malaria we demonstrate that the generation of protective IL10(+)IFN-γ(+) Th1 cells is dependent on IL-27 signaling, and independent of IL-21

Contributos para a construção de um texto foneticamente equilibrado para o Português-Europeu Contributions to the elaboration of a phonetically balanced text for the European-Portuguese

OBJECTIVO: o objectivo deste estudo consiste na criação de um Texto Foneticamente Equilibrado para o Português-Europeu (PE) designado "O Sol". MÉTODO: quatro sujeitos da região de Setúbal, entre [21-49] anos (dois do sexo feminino e dois do masculino) leram em voz alta o texto "O Sol". As gravações realizadas com Olympus (VN- 240PC e VN- 2100PC com microfones integrados) serviram para a contabilização dos fonemas produzidos. Os procedimentos foram: 1) a comparação entre as frequências relativas dos fonemas do "O Sol" e as frequências relativas descritas no PF_fone, através do coeficiente de correlação de Pearson e do teste de Mann-Whitney; 2) a comparação entre a transcrição larga e a estreita, verificando-se os fenómenos de coarticulação; e 3) a análise dos formatos silábicos. RESULTADOS: a análise estatística demonstrou que as frequências relativas de ocorrência dos fonemas do texto "O Sol" têm uma correlação forte com as do PF_fone (r = 0,924). As medianas das frequências relativas de ocorrência dos fonemas do texto foram significativamente iguais das do PF_fone (pPURPOSE: the aim of this study is to elaborate a Phonetically Balanced Text for the European-Portuguese (EP) called "O Sol" (The Sun). METHOD: four subjects (two females and two males) with [21-49] year-old read aloud the text. Recordings were obtained with Olympus (VN-240PC and VN-2100PC) and were used to account the produced phonemes. The procedures were: 1) the comparison between the relative frequency of the phonemes of "O Sol" and the relative frequency described in PF_fone through the correlation coefficient of Pearson and the Mann-Whitney, 2) the comparison between the large and short transcriptions in order to analyze the co-articulation phenomenon 3) the analysis of the syllabic formats. RESULTS: statistical analysis showed that relative frequency occurrence of phonemes of the text "O Sol" have a strong correlation with those of PF_fone (r = 0,924). The median values of the relative frequency occurrence of phonemes of "O Sol" were significantly equal to the PF_fone (p<.05). CONCLUSION: the text "O Sol (The Sun)" is close to an ideal phonetically balanced text, since it achieved the predefined assumptions. Phonologically, it shows the most common formats syllable in the EP. We verified a decrease in relative frequency of phonemes in the close transcription, due to co-articulation phenomenon. Future work will focus on increasing said sample

IL-27 Promotes IL-10 Production by Effector Th1 CD4 +

Infection with the malaria parasite, Plasmodium, is characterized by excessive inflammation. The establishment of a precise balance between the pro- and anti-inflammatory responses is critical to guarantee control of the parasite and survival of the host. Interleukin (IL)-10, a key regulatory cytokine produced by many cells of the immune system, has been shown to protect mice against pathology during acute Plasmodium chabaudi chabaudi AS model of malaria. However, the critical cellular source of IL-10 is still unknown. Here, we demonstrate that T cell-derived IL-10 is necessary for the control of pathology during acute malaria, as mice bearing specific deletion of Il10 in T cells fully reproduce the phenotype observed in Il10(−/−) mice, with significant weight loss, drop in temperature and increased mortality. Furthermore, we show that IFN-γ(+) Th1 cells are the main producers of IL-10 throughout acute infection, expressing high levels of CD44 and ICOS and low levels of CD127. Although Foxp3(+) regulatory CD4(+) T cells produce IL-10 during infection, highly activated IFN-γ(+) Th1 cells were shown to be the essential and sufficient source of IL-10 to guarantee protection against severe immune-mediated pathology. Finally, in this model of malaria we demonstrate that the generation of protective IL10(+)IFN-γ(+) Th1 cells is dependent on IL-27 signaling, and independent of IL-21