Electrochemical magneto-immunoassay for detection of zika virus antibody in human serum.

Zika virus (ZIKV) is a flavivirus transmitted by infected Aedes genus mosquitoes. An infected person may be asymptomatic or present symptoms such as fever, arthralgia, and in pregnancy it may lead to neurological disorders in the fetus, such as microcephaly. Based on the high dissemination potential of ZIVK and its similar antigen composition to other arboviruses, new approaches for selective virus detection are urgently needed. This work reports the development of an electrochemical immunoassay for detection of anti-ZIKV antibodies, using magnetic beads functionalized with recombinant protein derived from the non-structural protein 1 (ΔNS1-ZIKV) and anti-IgG antibodies labeled with horseradish peroxidase (HRP) enzyme. The magneto-immunoassay uses disposable microfluidic devices for detection of anti-ZIKV in serum samples. A linear response was obtained for a wide concentration range from 0.01 to 9.80 × 105 pg mL-1 (r2 = 0.982), with a limit of detection of 0.48 pg mL-1. The proposed immunoassay proved to be highly efficient for the detection of anti-ZIKV antibodies in serum, offering promising perspectives for the development of fast, simple, and affordable point-of-care diagnosis devices for ZIKV.

Electrochemical magneto-immunoassay for detection of zika virus antibody in human serum

Zika virus (ZIKV) is a flavivirus transmitted by infected Aedes genus mosquitoes. An infected person may be asymptomatic or present symptoms such as fever, arthralgia, and in pregnancy it may lead to neurological disorders in the fetus, such as microcephaly. Based on the high dissemination potential of ZIVK and its similar antigen composition to other arboviruses, new approaches for selective virus detection are urgently needed. This work reports the development of an electrochemical immunoassay for detection of anti-ZIKV antibodies, using magnetic beads functionalized with recombinant protein derived from the non-structural protein 1 (ΔNS1-ZIKV) and anti-IgG antibodies labeled with horseradish peroxidase (HRP) enzyme. The magneto-immunoassay uses disposable microfluidic devices for detection of anti-ZIKV in serum samples. A linear response was obtained for a wide concentration range from 0.01 to 9.80 × 105 pg mL−1 (r2 = 0.982), with a limit of detection of 0.48 pg mL−1. The proposed immunoassay proved to be highly efficient for the detection of anti-ZIKV antibodies in serum, offering promising perspectives for the development of fast, simple, and affordable point-of-care diagnosis devices for ZIKV.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers.

OBJECTIVES: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. METHODS: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. RESULTS: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. CONCLUSION: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.

Promotion of neutralizing antibody-independent immunity to wild-type and SARS-CoV-2 variants of concern using an RBD-Nucleocapsid fusion protein.

Both T cells and B cells have been shown to be generated after infection with SARS-CoV-2 yet protocols or experimental models to study one or the other are less common. Here, we generate a chimeric protein (SpiN) that comprises the receptor binding domain (RBD) from Spike (S) and the nucleocapsid (N) antigens from SARS-CoV-2. Memory CD4+ and CD8+ T cells specific for SpiN could be detected in the blood of both individuals vaccinated with Coronavac SARS-CoV-2 vaccine and COVID-19 convalescent donors. In mice, SpiN elicited a strong IFN-γ response by T cells and high levels of antibodies to the inactivated virus, but not detectable neutralizing antibodies (nAbs). Importantly, immunization of Syrian hamsters and the human Angiotensin Convertase Enzyme-2-transgenic (K18-ACE-2) mice with Poly ICLC-adjuvanted SpiN promotes robust resistance to the wild type SARS-CoV-2, as indicated by viral load, lung inflammation, clinical outcome and reduction of lethality. The protection induced by SpiN was ablated by depletion of CD4+ and CD8+ T cells and not transferred by antibodies from vaccinated mice. Finally, vaccination with SpiN also protects the K18-ACE-2 mice against infection with Delta and Omicron SARS-CoV-2 isolates. Hence, vaccine formulations that elicit effector T cells specific for the N and RBD proteins may be used to improve COVID-19 vaccines and potentially circumvent the immune escape by variants of concern.

Isolated specific IgA against respiratory viruses, Influenza or SARS-CoV-2, present in the saliva of a fraction of healthy and asymptomatic volunteers

Abstract Objectives: Defense against respiratory viruses depends on an immune response present in the mucosa, as saliva IgA secretes antibodies. During the pandemic, such as influenza or SARS-CoV-2, most infected patients are asymptomatic but retain specific antibodies post-infection. The authors evaluated IgG and IgA antibodies against SARS-CoV-2 and influenza in the saliva of asymptomatic volunteers, validated with controls or vaccinated individuals. Methods: The authors detected specific antibodies by validated conventional ELISA using natural SARS-CoV-2 antigens from infected Vero cells or capture-ELISA for influenza using natural antigens of the influenza vaccine. Results: Saliva from influenza-vaccinated individuals had more IgA than paired serum, contrary to the findings for specific IgG. In COVID-19-vaccinated samples, specific IgA in saliva increased after vaccination, but IgG levels were high after the first dose. In saliva from the asymptomatic population (226), anti-Influenza IgG was found in 57.5% (130) of samples, higher than IgA, found in 35% (79) of samples. IgA results were similar for SARS-CoV-2, with IgA present in 30% (68) of samples, while IgG was less present, in 44.2% (100) of samples. The proportion of influenza IgG responders was higher than that for SARS-CoV-2 IgG, but both populations presented similar proportions of IgA responders, possibly due to variable memory B cell survival. For both viruses, the authors found an important proportion (> 10%) of IgA+IgG- samples, suggesting the occurrence of humoral immunity directed to the mucosa. Conclusion: Specific antibodies for respiratory viruses in saliva are found in either infection or vaccination and are a convenient and sensitive diagnostic tool for host immune response.

Malassezia spp. in acoustic meatus of bats (Molossus molossus) of the Amazon Region, Brazil.

The yeasts of the Malassezia genus are opportunistic microorganisms and can cause human and animal infections. They are commonly isolated from the skin and auricular canal of mammalians, mainly dogs and cats. The present study was aimed to isolate Malassezia spp. from the acoustic meatus of bats (Molossus molossus) in the Montenegro region, "Rondônia", Brazil. From a total of 30 bats studied Malassezia spp. were isolated in 24 (80%) animals, the breakdown by species being as follows (one Malassezia sp. per bat, N = 24): 15 (62.5%) M. pachydermatis, 5 (20.8%) M. furfur, 3 (12.5%) M. globosa and 1 (4.2%) M. sympodialis. This study establishes a new host and anatomic place for Malassezia spp., as it presents the first report ever of the isolation of this genus of yeasts in the acoustic meatus of bats.

Crise aplástica da anemia falciforme condicionada pelo parvovírus B19 / Aplastic crisis in sickle cell anemia induced by parvovírus B19

Objetivo: Relatar um caso de uma criança de oito meses de idade, portadora de anemia falciforme, que apresenta quadro de crise aplástica transitória condicionada pelo parvovírus B19, salientando a raridade da ocorrência neste grupo etário. Material e métodos: Os autores fazem revisão de literatura e descrevem um caso de uma criança de oito meses, portadora de anemia falciforme, que se apresenta com febre, palidez intensa e reticulocitopenia. Ao ser internada é feita a hipóstese diagnóstica de crise aplástica transitória da anemia falciforme, e é submetida à investigação laboratorial com hemograma e pesquisa para parvovirus B19 através de sorologias por enzima imuno-ensaio (ELISA) e testes para detecção do antigeno por PCR. Resultados: Criança de oito meses de idade com anemia falciforme é admitida no hospital por febre e anemia profunda (HB = 3,8 por cento) e reticulocitopenia (2 por cento) sendo feito diagnóstico de crise aplástica transitória da anemia falciforme. As sorologias para parvovirus B19 mostram Ig M assim como também o PCR. A criança apresentou evolução favorável, recebendo transfusão de concentrado de glóbulos vermelhos e tendo alta após 4 dias. Conclusões: Estes caso ilustra a ocorrência da crise aplástica transitória da anemia falciforme condicionada pelo parvovirus B19 em uma criança com idade bastante precoce, fato pouco comum segundo relatos da literatura mundial e inédito na literatura nacional

Diagnostico da rubeola em pacientes com exantema / Rubella diagnosis in patients with exanthema

O pediatra frequentemente avalia criancas e adolescentes com exantema, ocasiao em que um dos diagnosticos etiologicos e o de rubeola. Esse diagnostico determina, para o paciente, a prescricao, unicamente, de sintomaticos...

Infecçöes virais em crianças internadas por doença aguda no trato respiratório inferior / Viral infections in hospitalized children affected by acute lower respiratory tract disease

Objetivo: Avaliar a freqüência dos principais vírus respiratórios em crianças internadas por doença do trato respiratório inferior em hospital universitário. Métodos: Foi realizado estudo prospectivo que incluiu duas coortes de crianças internadas no período de abril a julho de 1996. Os grupos selecionados segundo a presença de patologia deo trato respiratório inferior: Grupo A - com doença aguda (tempo de história inferior a sete dias), e B-sem patologia respiratória presente ou recente. Os parâmetros para definiçäo de doença do trato respiratório inferior incluíram alteraçöes na propedêutica pulmonar e/ou às radiografias simples do tórax. Foram pré-definidos critérios clínicos e radiológicos para classificaçäo das doenças do trato respiratório inferior no grupo A. Foi coletado, à internaçäo, material da nasofaringe de todas as crianças para detecçäo de vírus, através de cultura em meio celular e por imunofluorescência direta. Resultados: Foram selecionados 201 casos, 126 no grupo A e 75 no grupo B. Foram identificados vírus em 71 crianças do grupo A (56,4 por cento), enquanto eram somente 3 no grupo B (4,0 por cento). Nas crianças do grupo A foi predominante o vírus respiratório sincicial, detectado em 66 casos, sendo também identificados adenovírus (4) e influenza (1) em outros pacientes. No grupo B foram identificados dois pacientes com vírus respiratório sincicial e um com adenovírus. Os pacientes do grupo A que apresentavam vírus respiratório sincicial tinham mediana de idade (3 meses) menor do que os outros casos deste grupo (13 meses) e apresentavam mais sibilância ao exame físico (78,7 por cento versus 33,3 por cento). Este vírus esteve associado à maior parte dos casos de broquiolite (84 por cento) e à metade das pneumonias (46,4 por cento). Conclusöes: Os autores constataram uma significativa presença de vírus na maior parte dos casos de crianças internadas com patologia aguda do trato respitatório inferior...

Apresentacao clinica de 52 criancas com exantema causado pelo Herpesvirus Humano tipo 6 / Clinical profile of 52 children with exhantem caused by human herpvirus type 6

Os autores descrevem e analisam manifestacoes clinicas observadas em criancas com exantema causado pelo Herpesvirus tipo 6. Foi realizado estudo prospectivo no Servico de Pronto-Atendimento Pediatrico do Hospital Universitario da USP, durante 15 meses, com as criancas que apresentavam exantema generalizado nao-bolhoso. Os pacientes deste grupo inicial foram examinados e receberam um diagnostico clinico previo. Destas criancas, foram incluidas na casuistica do presente estudo apenas as criancas menores de tres anos, que tivessem comprovacao laboratorial da presenca do Herpesvirus tipo 6 no sangue. O estudo laboratorial foi realizado atraves da reacao de polimerizacao em cadeia do acido nucleico do Herpesvirus humano tipo 6, em linfocitos de sangue periferico...