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Article in English | WPRIM | ID: wpr-921355


Objective@#The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).@*Methods@#In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2.@*Results@#NAbs were detectable approximately 10 days post-onset (dpo) of symptoms and peaked at approximately 20 dpo. The NAb levels were slightly higher in young males and severe cases, while no significant difference was observed for the other classifications. In follow-up cases, the NAb titer had increased or stabilized in 18 cases, whereas it had decreased in 26 cases, and in one case NAbs were undetectable at the end of our observation. Although a decreasing trend in NAb titer was observed in many cases, the NAb level was generally still protective.@*Conclusion@#We demonstrated that NAb levels vary among all categories of COVID-19 patients. Long-term studies are needed to determine the longevity and protective efficiency of NAbs induced by SARS-CoV-2.

Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Female , Humans , Kinetics , Male , Middle Aged , Neutralization Tests , SARS-CoV-2
Medicina (B.Aires) ; 80(supl.3): 1-6, June 2020. ilus, graf, tab
Article in English | LILACS | ID: biblio-1135184


The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab’)2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab’)2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Humans , Animals , Immunoglobulin Fab Fragments/isolation & purification , Coronavirus Infections/therapy , Immune Sera/immunology , Antibodies, Viral/isolation & purification , Antibodies, Viral/immunology , Antibodies, Viral/chemistry , Argentina , Immunoglobulin G/isolation & purification , Immunoglobulin G/chemistry , Immunoglobulin Fab Fragments/chemistry , Neutralization Tests , Pandemics , Betacoronavirus , SARS-CoV-2 , COVID-19 , Horses
Braz. j. infect. dis ; 24(1): 85-88, Feb. 2020. tab, graf
Article in English | LILACS | ID: biblio-1089325


ABSTRACT The antigenic potential of seven immunogenic peptides of the dengue virus was evaluated in the sera of patients with dengue confirmed by IgM/IgG serology. Antibodies IgM and IgG against dengue virus peptides were analyzed by ELISA in 31 dengue sero-positive and 20 sero-negative patients. The P5 peptide showed significant IgG immunoreactivity mostly in the sera of patients with dengue without warning signs in comparison with patients with dengue with warning signs, correlating with mild disease. This finding suggests that the low antibody response against P5 epitope could be a risk factor for higher susceptibility to dengue virus infection with warning signs, and that P5 could be a potential antigen for vaccine development.

Humans , Male , Female , Child , Adolescent , Adult , Middle Aged , Aged , Young Adult , Peptides/immunology , Viral Envelope Proteins/immunology , Dengue Virus/immunology , Dengue Vaccines , Antibodies, Viral/immunology , Epitopes/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Enzyme-Linked Immunosorbent Assay , Statistics, Nonparametric , Dengue/immunology , Dengue/prevention & control , Antibody Formation , Antigens, Viral/immunology
Einstein (Säo Paulo) ; 18: eAO5078, 2020. tab
Article in English | LILACS | ID: biblio-1056051


ABSTRACT Objective: To evaluate the performance of indirect immunofluorescence for serological diagnosis of dengue virus in a population with high prevalence of arboviruses. Methods: Two-hundred serum samples from patients with clinical suspicion of dengue fever were tested by immunoenzymatic and indirect immunofluorescence assay BIOCHIP® mosaic. Specificity, sensitivity and Kappa coefficient were calculated. Discordant samples were tested by polymerase chain reaction for confirmation. Results: Of the 200 samples, 20% were positive and 80% negative for anti-dengue virus IgM antibodies in the immunoenzymatic test. Of the 40 positives, 25% were negative in indirect immunofluorescence. Of these ten discordant results, only 20% were also negative in the polymerase chain reaction (PCR). Of the 160 negatives in the immunoenzymatic test, 5% were positive in indirect immunofluorescence. Of these nine discordant results, 33% were positive in the PCR. The Kappa coefficient was 0.7 (0.572-0.829). Sensitivity and specificity of indirect immunofluorescence were respectively 75% and 94%. For anti-dengue virus IgG antibodies, of the 200 samples, 15.5% were positive and 84.5% were negative in the immunoenzymatic test. Of the 31 positives, 12.9% were negative in indirect immunofluorescence. Of these four discordant results, 25% were negative in the PCR. Of the 169 negatives, 8% were positive in indirect immunofluorescence. Of these 14 discordant results, 64% were also positive in the PCR. The Kappa coefficient was 0.695 (0.563-0.83). Sensitivity and specificity of indirect immunofluorescence were 87.1% and 91.7%, respectively. Conclusion: For diagnosis of acute infection, the immunoenzymatic test is enough, and the use of additional methods is not warranted. Replacing the immunoenzymatic test by indirect immunofluorescence would compromise the sensitivity for IgM. However, indirect immunofluorescence can distinguish three arboviruses simultaneously, an advantage during concomitant epidemics.

RESUMO Objetivo: Avaliar o desempenho da imunofluorescência indireta no diagnóstico sorológico de dengue em uma população com alta prevalência de arboviroses. Métodos: Duzentas amostras de soro de pacientes com suspeita clínica de dengue foram testadas por ensaio imunoenzimático e imunofluorescência indireta mosaico BIOCHIP®. Foram calculados especificidade, sensibilidade e coeficiente Kappa. Nas amostras discordantes, realizou-se reação em cadeia da polimerase como método confirmatório. Resultados: Das 200 amostras, 20% foram positivas e 80% negativas para IgM antivírus da dengue no ensaio imunoenzimático. Das 40 positivas, 25% foram negativas na imunofluorescência indireta. Destas dez negativas, apenas 20% eram também negativas na reação em cadeia da polimerase. Das 160 negativas no ensaio imunoenzimático, 5% foram positivas na imunofluorescência indireta. Por fim, dentre as nove discordantes, 33% tiveram vírus da dengue detectado na reação em cadeia da polimerase. O coeficiente Kappa foi 0,70 (0,57-0,82). Sensibilidade e especificidade por imunofluorescência indireta foram, respectivamente, 75% e 94%. Para IgG antivírus da dengue, de 200 amostras, 15,5% foram positivas e 84,5% negativas no ensaio imunoenzimático. Das 31 positivas, 12,9% foram negativas na imunofluorescência indireta. Destas quatro discordantes, 25% apresentaram vírus da dengue não detectado na reação em cadeia da polimerase. Das 169 negativas, 8% foram positivas na imunofluorescência indireta. Destas, 64% foram positivas também na reação em cadeia da polimerase. O coeficiente Kappa foi 0,695 (0,56-0,83). Sensibilidade e a especificidade por imunofluorescência indireta foram, respectivamente, 87,1% e 91,7%. Conclusão: Ensaio imunoenzimático seria suficiente para diagnóstico sorológico de infecção aguda, não justificando a incorporação da imunofluorescência indireta. Substituir ensaio imunoenzimático pela imunofluorescência indireta poderia comprometer a sensibilidade para IgM. Contudo, a imunofluorescência indireta auxilia diferenciar três arboviroses simultaneamente, sendo vantajoso em epidemias concomitantes.

Enzyme-Linked Immunosorbent Assay/methods , Fluorescent Antibody Technique, Indirect/methods , Dengue/diagnosis , Arboviruses/isolation & purification , Reference Standards , Brazil , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Enzyme-Linked Immunosorbent Assay/standards , Serologic Tests/methods , Serologic Tests/standards , Polymerase Chain Reaction , Sensitivity and Specificity , Fluorescent Antibody Technique, Indirect/standards , Dengue/immunology , Dengue Virus/isolation & purification , Antibodies, Viral/immunology
Einstein (Säo Paulo) ; 18: eRW4890, 2020. tab, graf
Article in English | LILACS | ID: biblio-1056050


ABSTRACT Objective To demonstrate the impact of pneumococcal conjugate vaccine in Streptococcus pneumoniae carriage status in children younger than 5 years in Latin America and the Caribbean. Methods A systematic literature review was carried out on the direct and indirect effects of pneumococcal vaccine in the carriage status, after implementation in childhood immunization programs. Studies carried out in children younger than 5 years were selected from the PubMed® and Virtual Health Library databases, and data collected after implementation of pneumococcal vaccine in Latin America and the Caribbean, between 2008 and 2018. Results From 1,396 articles identified, 738 were selected based on titles and abstracts. After duplicate removal, 31 studies were eligible for full-text reading, resulting in 6 publications for analysis. All selected publications were observational studies and indicated a decrease in the carriage and vaccine types, and an increase in the circulation of non-vaccine serotypes, such as 6A, 19A, 35B, 21 and 38. We did not identify changes in the antimicrobial resistance after vaccine implementation. Conclusion A decrease in the carriage status of vaccine types and non-vaccine types was detected. The continuous monitoring of pneumococcal vaccine effect is fundamental to demonstrate the impact of the carriage status and, consequently, of invasive pneumococcal disease, allowing better targeting approaches in countries that included pneumococcal vaccine in their immunization programs. Our study protocol was registered in PROSPERO ( under number CRD42018096719.

RESUMO Objetivo Demonstrar o impacto das vacinas pneumocócicas conjugadas no estado de portador de Streptococcus pneumoniae em crianças menores de 5 anos na América Latina e no Caribe. Métodos Foi realizada revisão sistemática da literatura sobre os efeitos diretos e indiretos da vacina pneumocócica no estado de portador em crianças menores de 5 anos, após a implantação da vacina nos calendários de imunização infantil. A partir de dados da PubMed®e da Biblioteca Virtual da Saúde, foram selecionados estudos de portador em crianças menores de 5 anos, com dados coletados após implementação da vacina de 2008 a 2018, na América Latina e no Caribe. Resultados Dos 1.396 artigos identificados, 738 foram selecionados mediante leitura de títulos e resumos. Após a extração dos duplicados, 31 foram elegíveis para leitura do texto completo, restando 6 artigos para análise. Todos os estudos selecionados eram observacionais e indicavam diminuição do portador e tipos vacinais, e aumento da circulação de sorotipos não vacinais, como 6A, 19A, 35B, 21 e 38. Não foi observada alteração na resistência antimicrobiana após a introdução da vacina. Conclusão Detectou-se redução no estado de portador, dos tipos vacinais e não vacinais. O monitoramento contínuo do efeito das vacinas pneumocócicas é fundamental, para demonstrar o impacto do estado de portador e, consequentemente, da doença pneumocócica invasiva, permitindo o melhor direcionamento nas ações em saúde para os países que incluíram a vacina no calendário de imunização. Nosso protocolo de estudo foi registrado no PROSPERO ( sob o número CRD42018096719.

Humans , Enzyme-Linked Immunosorbent Assay/methods , Fluorescent Antibody Technique, Indirect/methods , Dengue/diagnosis , Arboviruses/isolation & purification , Reference Standards , Brazil , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Enzyme-Linked Immunosorbent Assay/standards , Serologic Tests/methods , Serologic Tests/standards , Polymerase Chain Reaction , Sensitivity and Specificity , Fluorescent Antibody Technique, Indirect/standards , Dengue/immunology , Dengue Virus/isolation & purification , Antibodies, Viral/immunology
Mem. Inst. Oswaldo Cruz ; 115: e200225, 2020.
Article in English | SES-SP, LILACS, SES-SP | ID: biblio-1135239


In the near future, the overlap of Coronavirus disease 2019 (COVID-19) and dengue epidemics is a concrete threat in tropical regions. Co-epidemics of COVID-19 and dengue could be an overwhelming challenge for health systems in low- and middle-income countries. In this work, we investigated potential serological cross-reactions between COVID-19 and dengue patients. Among 32 COVID-19 positive sera, no positive Dengue virus (DENV) IgG/IgM results were observed. On the other hand, one false-positive result was observed among 44 DENV-positive sera tested for COVID-19 antibodies with each of the two rapid tests used. Further data on accuracy of COVID-19 diagnostic test are urgently warranted.

Humans , Pneumonia, Viral/immunology , Coronavirus Infections/immunology , Cross Reactions , Dengue/immunology , Antibodies, Viral/immunology , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Enzyme-Linked Immunosorbent Assay , Dengue Virus/immunology , Pandemics , Betacoronavirus/immunology , SARS-CoV-2 , COVID-19
Braz. j. med. biol. res ; 52(10): e8845, 2019. tab, graf
Article in English | LILACS | ID: biblio-1039251


Regucalcin is a soluble protein that is principally expressed in hepatocytes. Studies of regucalcin have mainly been conducted in animals due to a lack of commercially available kits. We aimed to develop an enzyme-linked immunosorbent assay (ELISA) to quantify serum regucalcin in patients with hepatitis B virus (HBV)-related disease. High-titer monoclonal antibodies and a polyclonal antibody to regucalcin were produced, a double-antibody sandwich ELISA method was established, and serum regucalcin was determined in 47 chronic hepatitis B (CHB) patients, 91 HBV-related acute-on-chronic liver failure (HBV-ACLF) patients, and 33 healthy controls. The ELISA demonstrated an appropriate linear range, and high levels of reproducibility, sensitivity, specificity, accuracy, and stability. The median serum regucalcin concentrations in HBV-ACLF and CHB patients were 5.46 and 3.76 ng/mL, respectively (P<0.01), which were much higher than in healthy controls (1.72 ng/mL, both P<0.01). For the differentiation of CHB patients and healthy controls, the area under curve (AUC) was 0.86 with a cut-off of 2.42 ng/mL, 85.7% sensitivity, and 78.8% specificity. In contrast, the AUC of alanine aminotransferase (ALT) was lower (AUC=0.80, P=0.01). To differentiate ACLF from CHB, the AUC was 0.72 with a cut-off of 4.26 ng/mL, 77.0% sensitivity, and 61.2% specificity while the AUC of ALT was 0.41 (P=0.07). Thus, we have developed an ELISA that is suitable for measuring serum regucalcin and have shown that serum regucalcin increased with the severity of liver injury due to HBV-related diseases, such that it appears to be more useful than ALT as a marker of liver injury.

Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Young Adult , Calcium-Binding Proteins/blood , Hepatitis B, Chronic/blood , Renal Insufficiency/blood , Severity of Illness Index , Enzyme-Linked Immunosorbent Assay/methods , Biomarkers/blood , Case-Control Studies , Reproducibility of Results , Sensitivity and Specificity , Hepatitis B, Chronic/virology , Renal Insufficiency/virology , Antibodies, Viral/immunology
Rev. Soc. Bras. Med. Trop ; 51(5): 591-595, Sept.-Oct. 2018. tab, graf
Article in English | LILACS | ID: biblio-957467


Abstract INTRODUCTION West Nile virus (WNV) immunoglobulin M (IgM) antibodies have been shown to persist for up to 500 days in certain patients. To evaluate the usefulness of immunoglobulin G (IgG) avidity assessment in the diagnosis of WNV infection, we analyzed 54 WNV IgM- and/or IgG-positive serum samples from 39 patients with neuroinvasive disease and 15 asymptomatic cases tested during a seroprevalence investigation. METHODS Serological tests (WNV IgM/IgG antibody detection, IgG avidity) were performed using commercially available enzyme-linked immunosorbent assays. RESULTS WNV IgM antibodies were detected in 47 (87%) samples. Acute/recent WNV infection was confirmed based on low/borderline avidity index (AI) in 44 IgM-positive samples (93.6%). In three IgM-positive samples (6.4%), high IgG AIs were detected, thus indicating persisting IgM antibodies from previous infections. All IgM-negative samples showed high AIs. Patients with WNV neuroinvasive disease tested within 30 days showed low AIs. In six patients tested 34-50 days after disease onset, AI was borderline (42%-60%), suggesting earlier WNV IgG maturation. Samples with the highest IgM values were associated with the lowest AIs (Spearman's rho coefficient -0.767, p < 0.001). CONCLUSIONS Our results indicate that IgG avidity differentiates current/recent WNV infection from persistent IgM seropositivity from the previous WNV transmission season both in patients with WNV neuroinvasive disease and in asymptomatic persons. A strong negative correlation between IgM antibody levels and AI indicates that in cases with very high IgM levels, determination of IgG avidity may not be necessary. As many patients showed rapid avidity maturation, low IgG avidity is indicative of WNV infection within the previous month.

Humans , West Nile Fever/diagnosis , West Nile virus/immunology , Immunoglobulin G/immunology , Antibodies, Viral/immunology , Antibody Affinity/immunology , Seasons , Immunoglobulin G/blood , Immunoglobulin M/blood , Enzyme-Linked Immunosorbent Assay , Antibodies, Viral/blood
Braz. j. infect. dis ; 22(2): 150-152, Mar.-Apr. 2018.
Article in English | LILACS | ID: biblio-1039211


ABSTRACT In the current effort to eliminate polio from the world, it is important to recognize and vaccinate susceptible groups, especially immunocompromised patients living in countries where attenuated polio vaccine is still used. In this report, we describe the frequency of protective antibodies in a small sample of adult SOT candidates in whom previous vaccination could be ascertained. Patients included in this report were selected among the participants of an ongoing prospective study carried out at the Reference Center for Special Immunobiologicals of the Evandro Chagas National Institute of Infectious Diseases in Rio de Janeiro, Brazil. Among the first 100 patients enrolled in this study, only seven adult SOT candidates had proven polio vaccination at childhood. Three of these seven patients (43%) had no protective antibody titers to one or more poliovirus subtype before solid organ transplant. Proven childhood vaccination against polio does not reliably provide lifelong protective antibody titers for adult SOT candidates and should not be used as a criterion to analyze the need for vaccination in this population.

Humans , Male , Female , Adolescent , Adult , Young Adult , Poliomyelitis/prevention & control , Tissue Donors , Organ Transplantation , Poliovirus Vaccines/therapeutic use , Poliomyelitis/immunology , Poliomyelitis/epidemiology , Vaccines, Attenuated , Immunization , Immunocompromised Host , Antibodies, Viral/immunology
Medicina (B.Aires) ; 77(5): 353-357, oct. 2017. tab
Article in Spanish | LILACS | ID: biblio-894499


Candid#1 es la primera vacuna a virus vivo atenuado producida y registrada en Argentina. Se produce en el INEVH desde 2003 para prevenir la fiebre hemorrágica argentina y se obtiene mediante cosecha de sobrenadantes de cultivos de células diploides infectadas con una cepa atenuada del virus Junín, formulación y posterior liofilización. Su estabilidad es crucial para asegurar su efectividad. El objetivo de este trabajo fue evaluar la estabilidad de Candid#1 exponiéndola a distintas condiciones de temperatura y tiempo. Tres lotes producidos en 2003 fueron sometidos al siguiente esquema de almacenamiento: (a) vacuna reconstituida conservada entre 2 °C y 8 °C durante 8 días, (b) vacuna liofilizada conservada entre 2 °C y 8 °C durante 6 meses, y (c) vacuna liofilizada conservada entre -18 °C y -20 °C durante 10 años. La potencia fue evaluada en monocapa de células Vero bajo agar. Los resultados fueron: (a) Candid#1 reconstituida fue estable 8 días entre 2 °C y 8 °C, (b) Candid#1 liofilizada fue estable 2 meses entre 2 °C y 8 °C y (c) Candid#1 liofilizada fue estable 9 años entre -18 °C y -20 °C manteniendo todos sus atributos. Estos resultados permitieron establecer las siguientes condiciones de almacenamiento: reconstituida 12 horas entre 2 °C y 8 °C, liofilizada 30 días entre 2 °C y 8 °C y 9 años entre -18 °C y -20 °C. A la luz de estos resultados, se generaron cambios favorables en las condiciones de transporte, almacenamiento y distribución de la vacuna. Se implementó la instalación de freezers domésticos en centros estratégicamente distribuidos, permitiendo preservar stocks de vacuna y distribuir las dosis necesarias a vacunatorios.

Candid#1 is the first live attenuated vaccine produced and registered in Argentina. Produced since 2003 at the INEVH to prevent Argentine hemorrhagic fever, it is obtained by harvesting supernatants of diploid cells infected with an attenuated strain of Junin virus and subsequent lyophilization. The stability of this vaccine is crucial to ensure its effectiveness. This study was aimed to evaluate the stability of Candid#1 by exposing it to different time and temperature conditions. Three vaccine batches produced in 2003 were analysed according to the following storage scheme: (a) reconstituted vaccine at 2 °C to 8°C for 8 days; (b) lyophilized vaccine at 2 °C to 8 °C for 6 months; (c) lyophilized vaccine at -18 °C to -20 °C for 10 years. The potency was assessed in Vero cell monolayers under agar. The results were: (a) reconstituted vaccine was stable between 2 °C and 8 °C for 8 days, (b) lyophilized vaccine was stable between 2 °C and 8 °C for 2 months, and (c) lyophilized vaccine was stable 9 years between -18 °C and -20 °C, keeping all its properties. These results allowed us to establish the following storage conditions and expiration times for Candid#1: (a) reconstituted: 12 hours between 2 °C and 8 °C, (b) lyophilized: 30 days between 2 °C and 8 °C and (c) lyophilized: 9 years between -18 °C and -20 °C. Based on our results, favorable changes were made in the conditions of transport, storage and distribution of the vaccine. Domestic freezers in strategically located centers were installed, allowing the preservation of vaccine stocks for distribution to secondary vaccination centers.

Humans , Viral Vaccines/immunology , Arenaviruses, New World/immunology , Drug Storage/methods , Hemorrhagic Fever, American/prevention & control , Antibodies, Viral/immunology , Argentina , Vaccines, Attenuated/immunology , Drug Stability
Rev. Soc. Bras. Med. Trop ; 48(5): 514-523, Sept.-Oct. 2015. tab, graf
Article in English | LILACS | ID: lil-763338


ABSTRACTINTRODUCTION:While no single factor is sufficient to guarantee the success of influenza vaccine programs, knowledge of the levels of immunity in local populations is critical. Here, we analyzed influenza immunity in a population from Southern Brazil, a region with weather conditions that are distinct from those in the rest of country, where influenza infections are endemic, and where greater than 50% of the population is vaccinated annually.METHODS:Peripheral blood mononuclear cells were isolated from 40 individuals. Of these, 20 had received the H1N1 vaccine, while the remaining 20 were unvaccinated against the disease. Cells were stimulated in vitro with the trivalent post-pandemic influenza vaccine or with conserved major histocompatibility complex I (MHC I) peptides derived from hemagglutinin and neuraminidase. Cell viability was then analyzed by [3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide)]-based colorimetric assay (MTT), and culture supernatants were assayed for helper T type 1 (Th1) and Th2-specific cytokine levels.RESULTS:Peripheral blood lymphocytes from vaccinated, but not unvaccinated, individuals exhibited significant proliferation in vitro in the presence of a cognate influenza antigen. After culturing with vaccine antigens, cells from vaccinated individuals produced similar levels of interleukin (IL)-10 and interferon (IFN)-γ, while those from unvaccinated individuals produced higher levels of IFN-γ than of IL-10.CONCLUSIONS:Our data indicate that peripheral blood lymphocytes from vaccinated individuals are stimulated upon encountering a cognate antigen, but did not support the hypothesis that cross-reactive responses related to previous infections can ameliorate the immune response. Moreover, monitoring IL-10 production in vaccinated individuals could comprise a valuable tool for predicting disease evolution.

Adult , Humans , Young Adult , Antibodies, Viral/immunology , Influenza A Virus, H1N1 Subtype/immunology , Influenza Vaccines/immunology , Influenza, Human/immunology , Lymphocytes/immunology , Antibodies, Viral/blood , Brazil/epidemiology , /immunology , Cross-Sectional Studies , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Interferon-gamma/biosynthesis , /biosynthesis , Leukocytes, Mononuclear/immunology , Pandemics
Mem. Inst. Oswaldo Cruz ; 110(5): 624-628, Aug. 2015. tab, ilus
Article in English | LILACS | ID: lil-755899


In the Americas, hantaviruses cause severe cardiopulmonary syndrome (HCPS) with a high fatality rate. Hantavirus infection is commonly diagnosed using serologic techniques and reverse transcription-polymerase chain reaction. This paper presents a novel plaque reduction neutralisation test (PRNT) for detecting antibodies to Brazilian hantavirus. Using PRNT, plaque detection was enhanced by adding 0.6% of dimethyl sulfoxide into the overlay culture medium of the infected cells. This procedure facilitated clear visualisation of small plaques under the microscope and provided for easy and accurate plaque counting. The sera from 37 HCPS patients from the city of Ribeirão Preto, Brazil was evaluated for the Rio Mamoré virus (RIOMV) using PRNT. Six samples exhibited neutralising antibodies; these antibodies exhibited a low titre. The low level of seropositive samples may be due to fewer cross-reactions between two different hantavirus species; the patients were likely infected by Araraquara virus (a virus that has not been isolated) and RIOMV was used for the test. This assay offers a new approach to evaluating and measuring neutralising antibodies produced during hantavirus infections and it can be adapted to other hantaviruses, including viruses that will be isolated in the future.


Humans , Antibodies, Viral/blood , Hantavirus Pulmonary Syndrome/diagnosis , Neutralization Tests/methods , Antibodies, Viral/immunology , Enzyme-Linked Immunosorbent Assay , Hantavirus Pulmonary Syndrome/virology , Hantavirus/growth & development , Hantavirus/immunology , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Viral Plaque Assay
Ciênc. saúde coletiva ; 20(2): 441-448, 02/2015. tab
Article in Portuguese | LILACS | ID: lil-742219


Objetivou-se analisar as internações por condições sensíveis à atenção primária (ICSAP) específicas em mulheres e os fatores que determinam ou influenciam a ocorrência dessas internações (fatores socioeconômicos, sociodemográficos e controle de saúde) por meio de um inquérito de morbidade hospitalar realizado com amostra de 429 mulheres internadas em hospitais conveniados ao Sistema Único de Saúde. O percentual de ICSAP foi 49,42% (n = 212), com destaque para as internações específicas do sexo feminino 19,35% (n = 83). Associaram ao risco de internar por CSAP: idade superior a 60 anos, baixa escolaridade, internação prévia, realização de controle regular de saúde, falta de vínculo com a Estratégia Saúde da Família (ESF) e ser gestante. As causas evidentes foram as condições relacionadas à gravidez, ao parto e ao puerpério e às inflamações nos órgãos pélvicos femininos. Os resultados sugerem falhas no atendimento ambulatorial que deveria ser oportuno e resolutivo no contexto da saúde da mulher.

The scope of this paper was to analyze female-specific sensitive hospitalization occurring in primary care conditions and factors that determine or affect the occurrence of such hospitalizations (social, economic and demographic factors; health control). Analysis was performed by surveys on hospital morbidity with a sample of 429 females attended in Unified Health System (SUS) contracted hospitals. The sensitive hospitalizations percentage in primary care reached 49.42% (n = 212), highlighting female-specific hospitalization at 19.35% (n = 83). Hospitalization risks comprised elderly people over sixty, low schooling, previous hospitalizations, normal health control, lack of association with the Family Health Strategy and pregnancy. Evident causes were related to conditions of pregnancy, childbirth, post-partum and inflammations of the female pelvic organs. Results suggested flaws in outpatient attendance that should be adequate and provide solutions in women’s health.

Humans , Infant , Bacterial Proteins/immunology , Carrier Proteins/immunology , Diphtheria-Tetanus-Pertussis Vaccine/adverse effects , Diphtheria-Tetanus-Pertussis Vaccine/immunology , Haemophilus Vaccines/adverse effects , Haemophilus Vaccines/immunology , Immunoglobulin D/immunology , Lipoproteins/immunology , Pneumococcal Vaccines/adverse effects , Pneumococcal Vaccines/immunology , Poliovirus Vaccine, Inactivated/adverse effects , Poliovirus Vaccine, Inactivated/immunology , Antibodies, Bacterial/immunology , Antibodies, Viral/immunology , Diphtheria-Tetanus-Pertussis Vaccine/administration & dosage , Haemophilus Vaccines/administration & dosage , Immunization Schedule , Netherlands , Pneumococcal Vaccines/administration & dosage , Poliovirus Vaccine, Inactivated/administration & dosage , Vaccination , Vaccines, Conjugate , Vaccines, Combined/administration & dosage , Vaccines, Combined/adverse effects , Vaccines, Combined/immunology
Article in English | LILACS | ID: biblio-962171


Dengue, a disease caused by any of the four serotypes of dengue viruses, is the most important arthropod-borne viral disease in the world in terms of both morbidity and mortality. The infection by these viruses induces a plethora of clinical manifestations ranging from asymptomatic infections to severe diseases with involvement of several organs. Severe forms of the disease are more frequent in secondary infections by distinct serotypes and, consequently, a dengue vaccine must be tetravalent. Although several approaches have been used on the vaccine development, no vaccine is available against these viruses, especially because of problems on the development of a tetravalent vaccine. Here, we describe briefly the vaccine candidates available and their ability to elicit a protective immune response. We also discuss the problems and possibilities of any of the vaccines in final development stage reaching the market for human use.

Dengue, doença causada por qualquer um dos quatro sorotipos dos vírus dengue, é atualmente a mais importante doença viral transmitida por artrópodos em todo o mundo, tanto em termos de morbidade como de mortalidade. A infecção por estes vírus causa grande variedade de manifestações clínicas, desde infecções assintomáticas até doenças graves com envolvimento de diversos órgãos. As formas graves da dengue são mais frequentes em infecções secundárias por sorotipos diferentes e, por esta razão, a vacina contra a dengue deve ser tetravalente. Embora várias estratégias tenham sido usadas no desenvolvimento de vacinas contra a dengue, não há ainda nenhuma vacina disponível, particularmente por problemas no desenvolvimento de uma vacina tetravalente. Aqui, descreve-se brevemente os candidatos vacinais disponíveis e a capacidade de eles induzirem resposta imune protetora contra novas infecções. Ainda, discutimos os problemas e as possibilidades de liberação, para uso em seres humanos, de qualquer uma das vacinas em fase final de desenvolvimento

Humans , Dengue/prevention & control , Dengue Vaccines , Brazil , Clinical Trials as Topic , Drug Approval , Dengue Virus/immunology , Antibodies, Viral/immunology
Mem. Inst. Oswaldo Cruz ; 109(3): 335-339, 06/2014. tab
Article in English | LILACS | ID: lil-711723


A non-controlled longitudinal study was conducted to evaluate the combined vaccine against measles, mumps and rubella (MMR) immunogenicity in 150 children vaccinated in the routine of three health units in the city of Rio de Janeiro, Brazil, 2008-2009, without other vaccines administered during the period from 30 days before to 30 days after vaccination. A previous study conducted in Brazil in 2007, in 1,769 children ranging from 12-15 months of age vaccinated against yellow fever and MMR simultaneously or at intervals of 30 days or more between doses, had shown low seroconversion for mumps regardless of the interval between administration of the two vaccines. The current study showed 89.5% (95% confidence interval: 83.3; 94.0) seroconversion rate for mumps. All children seroconverted for measles and rubella. After revaccination, high antibody titres and seroconversion rates were achieved against mumps. The results of this study and others suggest that two MMR doses confer optimal immunoresponses for all three antigens and the possible need for additional doses should be studied taking into account not only serological, but also epidemiological data, as there is no serological correlate of protection for mumps.

Female , Humans , Infant , Male , Antibodies, Viral/immunology , Measles-Mumps-Rubella Vaccine/immunology , Mumps/immunology , Seroconversion , Antibodies, Viral/blood , Brazil , Immunization Schedule , Longitudinal Studies , Measles-Mumps-Rubella Vaccine/administration & dosage , Measles/immunology , Mumps/prevention & control , Rubella/immunology
Mem. Inst. Oswaldo Cruz ; 109(2): 168-173, abr. 2014. tab
Article in English | LILACS | ID: lil-705810


Immunocompromised patients may develop severe chronic anaemia when infected by human parvovirus B19 (B19V). However, this is not the case in human immunodeficiency virus (HIV)-infected patients with good adherence to highly active antiretroviral treatment (HAART). In this study, we investigated the clinical evolution of five HIV-infected patients receiving HAART who had B19V infections confirmed by serum polymerase chain reaction. Four of the patients were infected with genotype 1a strains and the remaining patient was infected with a genotype 3b strain. Anaemia was detected in three of the patients, but all patients recovered without requiring immunoglobulin and/or blood transfusions. In all cases, the attending physicians did not suspect the B19V infections. There was no apparent relationship between the infecting genotype and the clinical course. In the HAART era, B19V infections in HIV-positive patients may be limited, subtle or unapparent.

Adult , Female , Humans , Male , Middle Aged , Antibodies, Viral/blood , HIV Infections/complications , Parvoviridae Infections/immunology , /immunology , /isolation & purification , Antiretroviral Therapy, Highly Active , Anemia/complications , Anemia/diagnosis , Antibodies, Viral/immunology , Biomarkers/blood , Genotype , HIV Infections/drug therapy , Medication Adherence , Polymerase Chain Reaction , Parvoviridae Infections/complications , /genetics
Braz. j. infect. dis ; 18(1): 65-70, Jan-Feb/2014. tab, graf
Article in English | LILACS | ID: lil-703041


Objectives: To analyze the immunogenicity of virus-like particles (VLP) of human papillomavirus type 16 (HPV16) isolated in East China and the adjuvant potential of interleukin-12 (IL-12). Methods: The variant HPV16 L1VLP expressed in sf9 insect cells were purified with cesium chloride gradient centrifugation. BALB/c mice were vaccinated with VLP (L1N), VLP with Freund's adjuvant (L1A) or VLP with IL-12 recombinant plasmid (L1P). HPV16 VLP specific IgG and IFN-γ level in the serum were detected by ELISA, and the percentage of CD4+ and CD8+ in spleen cells was detected with flow cytometry. Results: The titers of serum IgG antibodies in vaccinated groups were higher than in negative control and the serum antibodies mainly recognized conformation-dependent HPV16 VLP epitopes. Splenic CD4+ and CD8+ T cell subsets increased after vaccination in every experimental group, and CD8+ increased obviously in L1P group. The ratio of CD4+/CD8+ decreased in L1P group and increased in the other two groups, compared to control group. Vaccination induced specific secretion of IFN-γ in the serum of vaccinated group (p < 0.05), especially in the L1P group. Conclusions: VLP of HPV16 variant strain isolated in East China could induce humoral immunity and cellular immunity in mice, and IL-12 recombinant plasmid can enhance cellular immunity. .

Animals , Female , Humans , Mice , /immunology , /blood , /genetics , Papillomavirus Infections/prevention & control , Vaccines, Virus-Like Particle/immunology , Adjuvants, Immunologic , Antibodies, Viral/blood , Antibodies, Viral/immunology , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Immunity, Cellular/immunology , Immunoglobulin G/blood , Immunoglobulin G/immunology , /immunology , Mice, Inbred BALB C , Molecular Sequence Data , Papillomavirus Infections/immunology
Article in English | WPRIM | ID: wpr-191849


Currently, killed-virus and modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccines are used to control porcine reproductive and respiratory syndrome. However, both types of vaccines have inherent drawbacks; accordingly, the development of novel PRRSV vaccines is urgently needed. Previous studies have suggested that yeast possesses adjuvant activities, and it has been used as an expression vehicle to elicit immune responses to foreign antigens. In this report, recombinant Kluyveromyces lactis expressing GP5 of HP-PRRSV (Yeast-GP5) was generated and immune responses to this construct were analyzed in mice. Intestinal mucosal PRRSV-specific sIgA antibody and higher levels of IFN-gamma in spleen CD4+ and CD8+ T cells were induced by oral administration of Yeast-GP5. Additionally, Yeast-GP5 administered subcutaneously evoked vigorous cell-mediated immunity, and PRRSV-specific lymphocyte proliferation and IFN-gamma secretion were detected in the splenocytes of mice. These results suggest that Yeast-GP5 has the potential for use as a vaccine for PRRSV in the future.

Administration, Oral , Animals , Antibodies, Viral/immunology , B-Lymphocytes/immunology , Enzyme-Linked Immunosorbent Assay , Immunity, Cellular , Immunity, Mucosal , Injections, Subcutaneous , Kluyveromyces/genetics , Mice , Mice, Inbred BALB C , Porcine respiratory and reproductive syndrome virus/immunology , Recombinant Proteins/genetics , T-Lymphocytes/immunology , Viral Envelope Proteins/genetics , Viral Vaccines/administration & dosage