Expression of TIGIT, PD-1 and HLA-DR/CD38 markers on CD8-T cells of children and adolescents infected with HIV and uninfected controls

ABSTRACT Immune exhaustion and senescence are scarcely studied in HIV-pediatric patients. We studied the circulatory CD8 T cells activation/exhaustion and senescent phenotype of children and adolescents vertically infected with HIV or uninfected controls based on the expression of human leukocyte antigen (HLA-DR), CD38, T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), programmed death 1 (PD-1) and CD57 by flow cytometry, during approximately one year. Eleven HIV-infected (HI) and nine HIV-uninfected (HU) children/adolescents who received two doses or one dose of meningococcal C conjugate vaccine (MenC), respectively, were involved in this study. Blood samples were collected before the immunization (T0), 1-2 months after the first dose (T1), and 1-2 months after the second dose (T2), which was administered approximately one year after the first one. HI patients not receiving combined antiretroviral therapy (cART) showed a higher frequency of CD8 T cells TIGIT+, PD-1+ or CD57+, as well as a higher frequency of CD8 T cells co-expressing CD38/HLA-DR/TIGIT or CD38/HLA-DR/PD-1 when compared to HI treated or HU individuals, at all times that they were assessed. CD8 T cells co-expressing CD38/DR/TIGIT were inversely correlated with the CD4/CD8 ratio but positively associated with viral load. The co-expression of CD38/DR/TIGIT or CD38/DR/PD-1 on CD8 T cells was also inversely associated with the CD4 T cells expressing co-stimulatory molecules CD127/CD28. The results showed a higher expression of exhaustion/senescence markers on CD8 T cells of untreated HI children/adolescents and its correlations with viral load.

Diphtheria-neutralizing antibody levels in healthy adults from Rio de Janeiro, Brazil

In Brazil, until 2004, the immunization policy against diphtheria involved childhood vaccination with no official routine booster dose administered after 15 years of age. This study assessed functional antibody levels against diphtheria among blood donors. A total of 140 blood samples were collected, and diphtheria antitoxin levels were evaluated by Vero cell neutralization test. The mean age of the population was 34 years old (range: 18-61 years); 37.8 percent females and 62.2 percent males. Overall, 30.7 percent (95 percent, CI: 23.4-38.7) individuals presented neutralizing antitoxin antibody titers < 0.01 IU/ml; 42.1 percent (95 percent, CI: 34.1-50.4) showed values between 0.01-0.09 IU/ml and, 27.1 percent (95 percent, CI: 20.2-34.9) had ³ 0.1 IU/ml. In the subgroup of individuals with history of diphtheria immunization during childhood (85 percent), a number of 28.5 percent showed unprotective levels of circulating neutralizing antibody (< 0.01 IU/ml). Despite the continuous progress of immunization programs directed to Brazilian population, currently healthy adults remain susceptible to diphtheria.

Induction of iron regulated proteins during normal growth of Neisseria meningitidis in a chemically defined medium

A expressao das proteinas reguladas pelo ferro (IRPs), in vitro, tem sido obtida pela adicao de quelantes de ferro ao meio de cultura, apos o crescimento bacteriano, na presenca de fonte de ferro organico. Neste estudo foram investigados aspectos da maxima expressao das IRPs de meningococo durante o crescimento normal, em condicoes de cultura definidas, utilizando-se o meio de Catlin e os caldos Mueller-Hinton e Tryptic Soja (TSB). Foram avaliadas as melhores condicoes para se obter vesiculas de membrana externa (OMVs) contendo IRPs para uso em vacina de meningococo B....

Imunidade conferida por vacinas anti-meningocócicas / Immunity confered by anti-meningococci vaccines

Em razäo da recente epidemia de doença meningocócica causada por N. meningitidis B na Grande Säo Paulo, Brasil, foi feita revisäo das epidemias dessa doença ocorridas no Brasil desde o início do século e uma análise das vacinas atuais contra N. meningitidis A, C, Y e W135. Também säo discutidos os mais recentes avanços no desenvolvimento e aplicaçäo de vacina contra N. meningitidis B, um desafio constante para os maiores centros de pesquisa de todo o mundo

Utilizaçäo do meio de cultura novobiocina-nitrato-sacarose (NNS) no diagnóstico presuntivo de staphylococcus saprophyticus / Use of NNS (Novobiocin-Nitrate-Sucrose) medium to differentiate staphylococcus saprophyticus from other coagulase-negative staphylococci

O meio de cultura NNS, constituído de púrpura de bromocresol, nitrato de potássio, sacarose e novobiocina, foi utilizado na diferenciaçäo de Staphylococcus saprophyticus isolados de urina. Na formulaçäo do meio NNS, a resistência à novobiocina, característica normalmente utilizada no diagnóstico presuntivo de Staphylococcus saprophyticus, foi associada a sua capacidade de utilizar a sacarose e à ausência da enzima nitrato-redutase, visando a diferenciaçäo deste microorganismo dos demais estafilococos coagulase negativa, inclusive os igualmente resistentes à novobiocina (STAPHYLOCOCCUS COHNII, STAPHYLOCOCCUS XYLOSUS E STAPHYLOCOCCUS SCIURI). Os Staphylococcus Cohnii näo utilizam a sacarose (88% das cepas), enquanto os Staphylococcus xylosus e Staphylococcus sciuri reduzem nitrato a nitrito em 100 e 80% das cepas, respectivamente. De 74 cepas de estafilococos coagulase negativa isoladas de urina, 49 (66,2%) cepas de Staphylococcus saprophyticus foram diferenciadas pelo meio NNs, tendo sido obtidos resultados de valor predicativo de resultado positivo de 100%, sensibilidade de 95,9%, especificidade de 100% e eficiência de 97,2%...