BackgroundPolymerized allergoids coupled to nonoxidized mannan (PM‐allergoids) may represent novel vaccines targeting dendritic cells (DCs). PM‐allergoids are better captured by DCs than native allergens and favor Th1/Treg cell responses upon subcutaneous injection. Herein we have studied in mice the in vivo immunogenicity of PM‐allergoids administered sublingually in comparison with native allergens.MethodsThree immunization protocols (4‐8 weeks long) were used in Balb/c mice. Serum antibody levels were tested by ELISA. Cell responses (proliferation, cytokines, and Tregs) were assayed by flow cytometry in spleen and lymph nodes (LNs). Allergen uptake was measured by flow cytometry in myeloid sublingual cells.ResultsA quick antibody response and higher IgG2a/IgE ratio were observed with PM‐allergoids. Moreover, stronger specific proliferative responses were seen in both submandibular LNs and spleen cells assayed in vitro. This was accompanied by a higher IFNγ/IL‐4 ratio with a quick IL‐10 production by submandibular LN cells. An increase in CD4+ CD25high FOXP3+ Treg cells was detected in LNs and spleen of mice treated with PM‐allergoids. These allergoids were better captured than native allergens by antigen‐presenting (CD45+ MHC‐II +) cells obtained from the sublingual mucosa, including DCs (CD11b+) and macrophages (CD64+). Importantly, all the differential effects induced by PM‐allergoids were abolished when using oxidized instead of nonoxidized PM‐allergoids.ConclusionOur results demonstrate for the first time that PM‐allergoids administered through the sublingual route promote the generation of Th1 and FOXP3+ Treg cells in a greater extent than native allergens by mechanisms that might well involve their better uptake by oral antigen‐presenting cells.

Early detection of SARS-CoV-2 is essential for a timely update of health policies and allocation of resources. Particularly, serological testing may allow individuals with low-risk of being contagious of SARS-CoV-2 to return to daily activities. Both private and academic initiatives have sought to develop serological assays to detect anti-SARS-CoV-2 antibodies. Herein, we compared five different assays in active healthcare personnel exposed to SARS-CoV-2 in a large center in Madrid, Spain, in a retrospective study. Median time lapse between polymerase chain-reaction (PCR) and serological testing was 11 days (7–21). All tests assessed IgM/IgG titers except for Euroimmun (IgA/IgG) and The Binding-Site (IgA/IgM/IgG). The highest concordance rate was observed between Dia.Pro and Euroimmun (75.76%), while it was lowest between The Binding-Site and Euroimmun (44.55%). The Binding-Site assay showed the highest concordance (85.52%) with PCR results. Considering PCR results as reference, Dia.Pro was the most sensitive test, although The Binding-Site assay exhibited the highest area under the curve (AUC; 0.85). OrientGene and MAGLUMI tests were performed in a smaller cohort with confirmed infection and thus were not adequate to estimate sensitivity and specificity. The Binding-Site assay presented the best joint sensitivity and specificity among all the tests analyzed in our cohort. Likewise, this serological assay presents a greater repertoire of antibodies and antigen-regions tested, which is why each individual’s humoral immunity is more accurately reflected. The better the immunity test, the most adequate the health strategy to take in terms of organization of consultations, surgery, and treatments in vulnerable patients. The three antibody classes (IgG/IgM/IgA) were determined jointly, which translates to an economic impact on healthcare. While their role in the protection status remains elusive, serological tests add a valuable tool in the early management of SARS-CoV-2 after known exposition.

El cribado de SARS-CoV-2 en mujeres asintomáticas admitidas en trabajo de parto se debe realizar con una combinación de técnicas microbiológicas: un estudio observacional RESUMEN Objetivo. El objetivo de este estudio es evaluar, en mujeres asintomáticas que acuden a urgencias en trabajo de parto, el valor de la detección sistemática con una combinación de reacción en cadena de la polimerasa con transcriptasa inversa (RT-PCR) y umbral del ciclo (Ct) y anticuerpos séricos. Material y métodos. Desde el 6 de mayo, todas las mujeres ingresadas para parto espontáneo se sometieron a RT-PCR en hisopos nasofaríngeos y anticuerpos específicos IgG del síndrome respiratorio agudo severo por coronavirus 2 (SARS-CoV-2) en suero que se realizaron como parte de la atención clínica de rutina en nuestra institución. Se registró el Ct de la PCR. Analizamos las primeras 100 mujeres admitidas consecutivamente para parto espontáneo en nuestra institución. Resultados. Nueve mujeres fueron positivas para SARS-CoV-2 en muestras nasofaríngeas (9%) y 13 (13%) presentaron anticuerpos específicos positivos del coronavirus. En general, la exposición previa a SARS-CoV-2 fue del 15%. La determinación de Ct (prueba de RT-PCR) de nuestros 9 pacientes positivos varió de 36 a 41 ciclos con una mediana de 40. El parto vaginal se produjo en el 94% de los casos y solo el 6% se sometió a una cesárea, siempre por razones obstétricas. No se observó transmisión fetal y el pronóstico materno y neonatal fue excelente. Conclusiones. Durante los episodios epidémicos en mujeres asintomáticas en trabajo de parto, las pruebas universales con RT-PCR (considerando la determinación de Ct) y la detección de anticuerpos, permiten una mejor interpretación de los resultados y evitan procedimientos de aislamiento innecesarios.