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.

Impact of nutritional iodine optimization on rates of thyroid hypoechogenicity and autoimmune thyroiditis: a cross-sectional, comparative study.

BACKGROUND: Since several countries have established mandatory food iodine fortification, there has been a decrease in rates of iodine deficiency disorders in parallel with an increase in prevalence of autoimmune thyroid diseases. This study compared the nutritional iodine status and the prevalence of autoimmune thyroiditis and thyroid hypoechogenicity on ultrasound in schoolchildren in São Paulo (Brazil) in two distinct periods of time in which fortified salt had different concentrations of iodine. METHODS: We conducted a cross-sectional study evaluating 206 children aged 7-14 years and without a history of thyroid disease. Assessments included measurements of thyrotropin (TSH), free thyroxine, antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-TG) antibodies, urinary iodine concentration, and thyroid ultrasound. RESULTS: Mean urinary iodine concentration was 165.1 µg/L. Eleven children (5.3%) were diagnosed with autoimmune thyroiditis based on at least two of four criteria adopted in our study: positive anti-TPO or anti-TG antibody, hypoechogenicity of the thyroid parenchyma on ultrasound, and a TSH >4.0 µU/mL. Comparing our results with those from a similar study conducted during a period in which concentrations of iodine in the salt were higher (median urinary iodine concentration >300 µg/L), we observed a trend toward a lower prevalence of autoimmune thyroiditis, although no definitive conclusion could be established. CONCLUSION: The current nutritional iodine status in our cohort was within optimal levels and lower than levels found in 2003. The prevalence of autoimmune thyroiditis seems to be decreasing in parallel with a decrease in iodine intake, although we could not reach a definitive conclusion.

Fatores interferentes na correlaçåo cito-histológica em papilomavírus (HPV) / Sample collection factors related to cyto-histologic discrepancies in papilomavirus detection

Cuidados com a colheita, critérios morfológicos, procedimentos técnicos e fases da infecçåo såo fatores fundamentais na integraçåo cito-histológica em Papilomavirus (HPV). Partindo de 22 biópsias cervicais, com infecçåo por HPV, segundo os critérios histológicos definidos por MEISELS e col., revimos as citologias correspondentes seguindo os critérios citológicos de Meisels e os de Schneider. Hibridaçåo "in situ" com sondas biotiniladas para HPV 6, 11, 16, 18, 31, 33, 35, 42, 43, 44, 45, 51, 52 e 56 e ampliaçåo pelo sistema avidina-biotina-peroxidase foi feita em novos cortes das biópsias. A revisåo da citologia revelou 16 casos com alteraçöes por HPV, dos quais 15 com representaçåo endocervical, que nåo foi detectada nos 6 restantes casos negativos. 18 casos (81,8 por cento) foram positivos para DNA-HPV, tendo 2 dos negativos áreas descoladas durante a reaçåo. Todos os casos foram fixados em excesso (m=18,5 dias nos negativos e 11,6 nos positivos). Este trabalho reafirma a importância da revisåo das amostras citológicas dos casos biopsiados, ressaltando a queståo da amostragem como causa dos falsos negativos. A hibridizaçåo mostrou-se útil mesmo em biópsias de rotina, mas a fixaçåo parece interferir com a reatividade do DNA viral