RBD and Spike DNA-Based Immunization in Rabbits Elicited IgG Avidity Maturation and High Neutralizing Antibody Responses against SARS-CoV-2.

Neutralizing antibodies (nAbs) are a critical part of coronavirus disease 2019 (COVID-19) research as they are used to gain insight into the immune response to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infections. Among the technologies available for generating nAbs, DNA-based immunization methods are an alternative to conventional protocols. In this pilot study, we investigated whether DNA-based immunization by needle injection in rabbits was a viable approach to produce a functional antibody response. We demonstrated that three doses of DNA plasmid carrying the gene encoding the full-length spike protein (S) or the receptor binding domain (RBD) of SARS-CoV-2 induced a time-dependent increase in IgG antibody avidity maturation. Moreover, the IgG antibodies displayed high cross neutralization by live SARS-CoV-2 and pseudoviruses neutralization assays. Thus, we established a simple, low cost and feasible DNA-based immunization protocol in rabbits that elicited high IgG avidity maturation and nAbs production against SARS-CoV-2, highlighting the importance of DNA-based platforms for developing new immunization strategies against SARS-CoV-2 and future emerging epidemics.

Yellow Fever as Cause of Death of Titi Monkeys (Callicebus Spp.).

From 2016 to 2018, an epidemic wave of yellow fever (YF) occurred in Brazil, affecting a large number of Platyrrhini monkeys. Titi monkeys (Callicebus spp.) were severely affected yet pathological characterizations are lacking. This study characterized epizootic YF in 43 titi monkeys (Callicebus spp.) with respect to the microscopic lesions in liver, kidney, spleen, heart, brain, and lung, as well as the distribution of immunolabeling for YF virus antigen, and the flaviviral load in the liver. Of 43 titi monkeys examined, 18 (42%) were positive for yellow fever virus (YFV) by immunohistochemistry or reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). Affected livers had consistent marked panlobular necrotizing hepatitis, lipidosis, and mild inflammation, with intense immunolabeling for YFV mainly in centrilobular hepatocytes (zone 1; P = .05). In the spleen, consistent findings were variable lymphoid depletion (10/11), lymphoid necrosis (lymphocytolysis; 4/11), and immunolabeling for YFV in histiocytic cells (3/16). The main finding in the kidney was multifocal acute necrosis of tubular epithelium (5/7) that was occasionally associated with intracytoplasmic immunolabeling for YFV (6/15). These data indicate that titi monkeys are susceptible to YFV infection, developing severe hepatic lesions and high viral loads, comparable to humans and Alouatta spp. Thus, Callicebus spp. may be reliable sentinels for YF surveillance.

Genomic Surveillance of Yellow Fever Virus Epizootic in São Paulo, Brazil, 2016 - 2018.

São Paulo, a densely inhabited state in southeast Brazil that contains the fourth most populated city in the world, recently experienced its largest yellow fever virus (YFV) outbreak in decades. YFV does not normally circulate extensively in São Paulo, so most people were unvaccinated when the outbreak began. Surveillance in non-human primates (NHPs) is important for determining the magnitude and geographic extent of an epizootic, thereby helping to evaluate the risk of YFV spillover to humans. Data from infected NHPs can give more accurate insights into YFV spread than when using data from human cases alone. To contextualise human cases, identify epizootic foci and uncover the rate and direction of YFV spread in São Paulo, we generated and analysed virus genomic data and epizootic case data from NHPs in São Paulo. We report the occurrence of three spatiotemporally distinct phases of the outbreak in São Paulo prior to February 2018. We generated 51 new virus genomes from YFV positive cases identified in 23 different municipalities in São Paulo, mostly sampled from NHPs between October 2016 and January 2018. Although we observe substantial heterogeneity in lineage dispersal velocities between phylogenetic branches, continuous phylogeographic analyses of generated YFV genomes suggest that YFV lineages spread in São Paulo at a mean rate of approximately 1km per day during all phases of the outbreak. Viral lineages from the first epizootic phase in northern São Paulo subsequently dispersed towards the south of the state to cause the second and third epizootic phases there. This alters our understanding of how YFV was introduced into the densely populated south of São Paulo state. Our results shed light on the sylvatic transmission of YFV in highly fragmented forested regions in São Paulo state and highlight the importance of continued surveillance of zoonotic pathogens in sentinel species.

Validation of chromogenic in situ hybridization reactions for DNA and RNA detection in formalin-fixed paraffin-embedded tissue / Validação das reações de hibridização in situ cromogênica para detecção de DNA e RNA em tecidos fixados em formalina e incluídos em parafina

ABSTRACT Introduction: Chromogenic in situ hybridization (CISH) is used alternatively to the traditional immunohistochemical methods for the diagnosis of infectious diseases in formalin-fixed paraffin-embedded samples, since it presents high sensitivity and specificity. This type of sample undergoes several chemical modifications during histological processing, and both poor and excessive fixation can impair sample quality, making it difficult to obtain good results. In CISH, it is common to use positive samples as quality control for the reactions; however, this practice does not provide any information regarding the preservation of the genetic material, nor does it avoid false-negative results. Objective: The objective of this study was to validate the deoxyribonucleic acid (DNA) (+) and (-), and ribonucleic acid (RNA) (+) and (-) control probes to be used as quality control for the samples, evaluating preservation of the genetic material. Materials and methods: Twelve histological sections were used (in quadruplicate, n = 48), prepared from a pool of tissues without microscopic changes related to infectious and/or inflammatory processes. The CISH protocol was conducted according to the manufacturer's instructions, standardized under the conditions of our laboratory, using commercial DNA and RNA probes chemically linked to digoxigenin. Results and conclusion: Our results were very satisfactory, showing high reproducibility, accuracy, sensitivity and analytical specificity, high predictive values for positive and negative assays and with zero ratio of false-positive and false-negative results, allowing the validation of this reaction.

RESUMEN Introducción: La hibridación in situ cromogénica (CISH) es una alternativa a los métodos tradicionales inmunohistoquímicos para el diagnóstico de enfermedades infecciosas en muestras fijadas en formoly embebidas enparafina, puesto que tiene alta sensibilidad y especificidad. Este tipo de muestra sufre diversas modificaciones químicas durante elprocesamiento histológico, y tanto la mala fijación cuanto la fijación excessiva pueden perjudicar la calidad de las muestras, impidiendo buenos resultados. En la CISH, es común el empleo de muestras positivas para control de calidad de reacciones; sin embargo, esta práctica no proporciona ninguna información acerca de la preservación del material genético. Objetivo: El propósito de este estudio ha sido realizar la validación de las sondas comerciales para ácido desoxirribonucleico (ADN) (+) y (-) y ácido ribonucleico (ARN) (+) y (-), para que sean utilizadas como control de calidad, evaluando la preservación del material genético en las muestras testadas. Material y métodos: Se incluyen en el estudio 12 cortes histológicos (en cuadruplicado, n = 48), confeccionados a partir de un pool de tejidos sin alteraciones microscópicas relacionadas con procesos infecciosos y/o inflamatorios. El protocolo de CISH se desarrolló de acuerdo a las instrucciones del fabricante y bajo las condiciones del nuestro laboratorio, haciendo uso de sondas comerciales de ADN y ARN quimicamente ligadas a digoxigenina. Resultados y conclusión: Nuestros resultados han sido muy satisfactorios, demostrando alta reproducibilidad, exactitud, sensibilidad, y especificidad analítica, así como altos valores predictivos para ensayos positivos y negativos, y con proporción nula de falsos negativos y falsos positivos, lo que ha permitido la validación de esa reacción.

RESUMO Introdução: A hibridização in situ cromogênica (CISH) é uma alternativa aos métodos tradicionais imuno-histoquímicospara diagnóstico de doenças infecciosas em amostras fixadas em formalina e incluídas em parafina, visto que apresenta grande sensibilidade e especificidade. Esse tipo de amostra sofre diversas modificações químicas durante o processamento histológico, e tanto a má fixação quanto a fixação em excesso podem prejudicar a qualidade das amostras, inviabilizando bons resultados. Na CISH, é comum a utilização de amostras positivas como controle de qualidade das reações; entretanto essa prática não fornece nenhuma informação a respeito da preservação do material genético, nem evita resultados falso-negativos nas amostras testadas. Objetivo: O objetivo deste estudo foi realizar a validação das sondas comerciais para ácido desoxirribonucleico (DNA) (+) e (-) e ácido ribonucleico (RNA) (+) e (-), para serem utilizadas como controle de qualidade, avaliando apreservação do material genético nas amostras testadas. Materiais e métodos: Foram utilizados 12 cortes histológicos (em quadruplicata, n = 48), confeccionados a partir de um pool de tecidos sem alterações microscópicas relacionadas com processos infecciosos e/ou inflamatórios. O protocolo de CISH foi conduzido de acordo com as instruções do fabricante e padronizado conforme as condições do nosso laboratório, utilizando sondas comerciais de DNA e RNA quimicamente ligadas à digoxigenina. Resultados e conclusão: Nossos resultados foram muito satisfatórios, demonstrando alta reprodutibilidade, acurácia, sensibilidade e especificidade analítica, bem como altos valores preditivos para ensaios positivos e negativos e com proporção nula de resultados falso-negativos e falso-positivos, o que possibilitou a validação dessa reação.

Experimental Zika virus infection induces spinal cord injury and encephalitis in newborn Swiss mice.

A widespread epidemic of Zika virus (ZIKV) infection was reported in 2015 in South and Central America, with neurological symptons including meningoencephalitis and Guillain-Barré syndrome in adults, besides an apparent increased incidence of microcephaly in infants born to infected mothers. It is becoming a necessity to have a trustworthy animal model to better understand ZIKV infection. In this study we used newborn white Swiss mice as a model to investigate the ZIKV strain recently isolated in Brazil. ZIKV was inoculated via intracerebral and subcutaneous routes and analysed through gross histopathology and immunohistochemistry. Here we demonstrated first that the intracerebral group (ICG) displayed severe cerebral lesions, with neuronal death, presence of apoptotic bodies, white matter degeneration and neutrophil perivascular cuffing. In the subcutaneous group (SCG), we observed moderate cerebral lesions, morphologically similar to that found in ICG and additional myelopathy, with architectural loss, marked by neuronal death and apoptotic bodies. Interestingly, we found an intense astrogliosis in brain of both groups, with increased immunoexpression of GFAP (glial fibrillary acidic protein) and presence of hypertrophic astrocytes. The spinal cord of subcutaneous group (SCG) exhibited reduction of astrocytes, but those positive for GFAP were hypertrophic and presented prolonged cellular processes. Finally significant lesions in the central nervous system (CNS) were present in newborn mice inoculated by both routes, but SCG method led to an important neurological manifestations (including myelopathy), during a longer period of time and appears for us to be a better model for ZIKV infection.

Morphologic, molecular and microenvironment factors associated with stromal invasion in breast ductal carcinoma in situ: Role of myoepithelial cells.

BACKGROUND: Ductal carcinoma in situ is the last step preceding invasive ductal carcinoma in breast carcinogenesis. OBJECTIVE: We investigated the role of myoepithelial cells and epithelium characteristics as predictors of the risk of stromal invasion. METHODS: We selected 236 cases with initial diagnosis of DCIS followed by surgical ressection distributed in groups 1 (without invasion) and 2 (with invasive carcinoma). RESULTS: The risk of stromal invasion after a DCIS diagnosis in biopsy was associated to triple-negative profile and loss of CD10 expression by myoepithelial cells, and inversely associated with CK5/6 expression by neoplastic cells and high expression of Smooth Muscle Myosin Heavy Chain (SMMHC) by myoepithelial cells. CONCLUSIONS: A combination of characteristics of epithelial and myoepithelial cells in DCIS in biopsy specimens is related to the risk of stromal invasion.

Basal cytokeratin as a potential marker of low risk of invasion in ductal carcinoma in situ.

OBJECTIVES: Biological markers that predict the development of invasive breast cancer are needed to improve personalized therapy for patients diagnosed with ductal carcinoma in situ. We investigated the role of basal cytokeratin 5/6 in the risk of invasion in breast ductal carcinoma in situ. METHODS: We constructed tissue microarrays using 236 ductal carcinoma in situ samples: 90 pure samples (group 1) and 146 samples associated with invasive carcinoma (group 2). Both groups had similar nuclear grades and were obtained from patients of similar ages. The groups were compared in terms of estrogen (ER) and progesterone receptor (PR) status, human epidermal growth factor receptor 2 (HER2) expression, cytokeratin 5/6 immunostaining, human epidermal growth factor receptor 1 (EGFR) membrane staining and molecular subtype, as indicated by their immunohistochemistry profiles. RESULTS: ER/PR-negative status was predictive of invasion, whereas HER2 superexpression and cytokeratin 5/6-positive status were negatively associated with invasion. Among the high-grade ductal carcinoma in situ cases, a triple-positive profile (positive for estrogen receptor, progesterone receptor, and HER2) and cytokeratin 5/6 expression by neoplastic cells were negatively associated with invasion. In the low-grade ductal carcinoma in situ subgroup, only cytokeratin 5/6 expression exhibited a negative association with the probability of invasion. CONCLUSION: The immunohistochemical expression of cytokeratin 5/6 by ductal carcinoma in situ epithelial cells may provide clinically useful information regarding the risk of progression to invasive disease.

Basal cytokeratin as a potential marker of low risk of invasion in ductal carcinoma in situ

OBJECTIVES: Biological markers that predict the development of invasive breast cancer are needed to improve personalized therapy for patients diagnosed with ductal carcinoma in situ. We investigated the role of basal cytokeratin 5/6 in the risk of invasion in breast ductal carcinoma in situ. METHODS: We constructed tissue microarrays using 236 ductal carcinoma in situ samples: 90 pure samples (group 1) and 146 samples associated with invasive carcinoma (group 2). Both groups had similar nuclear grades and were obtained from patients of similar ages. The groups were compared in terms of estrogen (ER) and progesterone receptor (PR) status, human epidermal growth factor receptor 2 (HER2) expression, cytokeratin 5/6 immunostaining, human epidermal growth factor receptor 1 (EGFR) membrane staining and molecular subtype, as indicated by their immunohistochemistry profiles. RESULTS: ER/PR-negative status was predictive of invasion, whereas HER2 superexpression and cytokeratin 5/6-positive status were negatively associated with invasion. Among the high-grade ductal carcinoma in situ cases, a triple-positive profile (positive for estrogen receptor, progesterone receptor, and HER2) and cytokeratin 5/6 expression by neoplastic cells were negatively associated with invasion. In the low-grade ductal carcinoma in situ subgroup, only cytokeratin 5/6 expression exhibited a negative association with the probability of invasion. CONCLUSION: The immunohistochemical expression of cytokeratin 5/6 by ductal carcinoma in situ epithelial cells may provide clinically useful information regarding the risk of progression to invasive disease. .