Navegando por Palavras-chave "Humoral immunity"

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    Doença de Chagas: aspectos gerais e imunopatogenia com foco para a atuação das células B-1 durante a infecção - uma revisão bibliográfica
    (Universidade Federal de São Paulo, 2022-12-07) Queiroz, Júlia Fonseca [UNIFESP]; Batista, Patricia Xander [UNIFESP]; http://lattes.cnpq.br/3620553457348403
    A doença de Chagas é uma zoonose negligenciada causada pelo protozoário Trypanosoma cruzi, que apresenta grande importância epidemiológica e que nos últimos anos tem se disseminado para fora da área endêmica. Ainda há diversos questionamentos acerca da imunopatogenia da doença de Chagas e a relação parasita-hospedeiro. Estudos realizados demonstram que é muito importante o balanço entre citocinas pró- e anti-inflamatórias para uma resposta imunológica mais efetiva ao parasito, mas não só isso, os efeitos protetivos dependem do background genético do hospedeiro, da virulência da cepa e do inóculo, o que denota grande desafio para o desenvolvimento de novas terapias. Diversos estudos já demonstraram que pacientes na fase crônica exibem anticorpos autorreativos que levam a piora do quadro clínico, mas ainda não se sabe como esses anticorpos são gerados. As células B-1, ainda pouco estudadas, dentre diversas funcionalidades, são capazes de produzir citocinas e anticorpos, incluindo autoanticorpos. Na fase aguda da doença de Chagas os anticorpos aparecem com baixa especificidade e podem perdurar durante longos períodos em mecanismo similar ao que acontece no lúpus eritematoso sistêmico, o que levanta o questionamento sobre a implicação desses anticorpos na evolução da doença. Na fase crônica, uma maior frequência de células B-1 e seu perfil anti-inflamatório parecem ser favoráveis para o hospedeiro. O presente estudo pretende conectar os aspectos gerais da doença de Chagas e a sua imunopatogenia, com foco para a atuação células B-1 durante a infecção, mesmo que poucos estudos tenham sido realizados acerca das implicações dessas células na patologia em questão. Essas células têm papel relevante na doença de Chagas e podem ser protagonistas ou mesmo direcionadoras para o desenvolvimento de novas estratégias terapêuticas no combate a T. cruzi se mais esforços forem realizados para estudá-las no contexto dessa parasitose.
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    Humoral immune response to measles and varicella vaccination in former very low birth weight preterm infants
    (Elsevier Brazil, 2018) Mariano Ferreira, Carolina Schlindwein; Abrao Aued Perin, Maria Cristina; de Moraes-Pinto, Maria Isabel; Simao-Gurge, Raquel Maria; Goulart, Ana Lucia; Weckx, Lily Yin; Nunes dos Santos, Amelia Miyashiro
    Introduction: Immune response to vaccination in infants born prematurely may be lower than in infants born at full-term. Some clinical factors might be associated with humoral immune response. Objectives: The objectives of this study were to compare the immune response to measles and varicella vaccination in infants born prematurely with those born at full-term and to analyze factors associated with measles and varicella antibody levels. Methods: Prospective study including two groups of infants aged 12 months. One group of infants born prematurely with birth-weight <1500 g and who were in follow-up at the outpatient clinic for preterm infants at the institution and other group of infants born at full-term. Infants with malformations, primary immunodeficiency diseases, born to HIV positive mothers or who had received plasma or immunoglobulin transfusions five months before or three weeks after vaccination were excluded. Plasma antibodies were measured by ELISA and factors associated with antibody levels were assessed by linear regression. Results: Sixty-five premature and 56 full-term infants were included. The percentage of immune individuals after vaccination against measles (100% vs. 100%) and varicella (92.5% vs. 93.2%) were similar in both groups, as well as the antibody levels against measles (2.393 vs. 2.412 Ul/mL
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    Immune response to tetanus booster in infants aged 15 months born prematurely with very low birth weight
    (Elsevier B.V., 2012-10-12) Perin, Maria Cristina Abrão Aued [UNIFESP]; Schlindwein, Carolina Frank [UNIFESP]; Moraes-Pinto, Maria Isabel de [UNIFESP]; Simao-Gurge, Raquel Maria [UNIFESP]; Mimica, Ana Flavia de Mello Almada [UNIFESP]; Goulart, Ana Lucia [UNIFESP]; Santos, Amélia Miyashiro Nunes dos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Objectives: To compare humoral and cellular immune responses to tetanus booster vaccination in infants born prematurely with those born at full term and identify factors associated with the humoral response.Methods: A prospective study was carried out on children born prematurely and with a birth weight <1500g and with infants born at full term. At 15 months (pre-vaccination) and 18 months (post-vaccination), anti-tetanus antibodies were measured by ELISA; the intracellular interferon-gamma percentages of CD4+ T and CD8+ T cells after in vitro stimulation with tetanus toxoid were determined by flow cytometry. Chi-squared or Fisher's exact test was used to compare categorical variables. Student's t-test or Mann-Whitney test was used to compare numerical variables. Regression analysis was performed to determine factors associated with humoral immunity. Statistical significance was considered if p < 0.05.Results: Sixty-four premature and 54 full-term infants were studied. the proportion of children immune against tetanus at 15 and 18 months was similar in both groups. the geometric mean of the antibodies was lower among the premature children at 15 months (p = 0.025) and was similar in both groups at 18 months (p = 0.852). the percentages of CD4+ and CD8+ T cells expressing intracellular IFN-gamma were similar in both groups at 15 and 18 months. Gestational age <32 weeks was associated with a reduction of 0.116 IU/mL in the level of antibodies at 15 months. Breastfeeding >6 months was associated with a 3.5-fold greater chance of optimal protective (>= 0.1 IU/mL) antibody level against tetanus at 15 months and an increase of 0.956 in the level of antibodies at 18 months.Conclusions: Humoral and cellular response following a tetanus booster was similar in both groups. Premature infants exhibited lower levels of anti-tetanus antibodies at 15 months of age, with the lowest levels in those born at a gestational age of less than 32 weeks. Breastfeeding was associated with greater levels of antibody against tetanus. (C) 2012 Elsevier B.V. All rights reserved.