Rapid response flow cytometric assay for the detection of antibody responses to SARS-CoV-2

Abstract SARS-CoV-2 has emerged as a previously unknown zoonotic coronavirus that spread worldwide causing a serious pandemic. While reliable nucleic acid–based diagnostic assays were rapidly available, only a limited number of validated serological assays were available in the early phase of the pandemic. Here, we evaluated a novel flow cytometric approach to assess spike-specific antibody responses.HEK 293T cells expressing SARS-CoV-2 spike protein in its natural confirmation on the surface were used to detect specific IgG and IgM antibody responses in patient sera by flow cytometry. A soluble angiotensin-converting-enzyme 2 (ACE-2) variant was developed as external standard to quantify spike-specific antibody responses on different assay platforms. Analyses of 201 pre-COVID-19 sera proved a high assay specificity in comparison to commercially available CLIA and ELISA systems, while also revealing the highest sensitivity in specimens from PCR-confirmed SARS-CoV-2-infected patients. The external standard allowed robust quantification of antibody responses among different assay platforms. In conclusion, our newly established flow cytometric assay allows sensitive and quantitative detection of SARS-CoV-2-specific antibodies, which can be easily adopted in different laboratories and does not rely on external supply of assay kits. The flow cytometric assay also provides a blueprint for rapid development of serological tests to other emerging viral infection

Protective mucosal immunity against SARS-CoV-2 after heterologous systemic prime-mucosal boost immunization

Several effective SARS-CoV-2 vaccines are currently in use, but effective boosters are needed to maintain or increase immunity due to waning responses and the emergence of novel variants. Here we report that intranasal vaccinations with adenovirus 5 and 19a vectored vaccines following a systemic plasmid DNA or mRNA priming result in systemic and mucosal immunity in mice. In contrast to two intramuscular applications of an mRNA vaccine, intranasal boosts with adenoviral vectors induce high levels of mucosal IgA and lung-resident memory T cells (TRM); mucosal neutralization of virus variants of concern is also enhanced. The mRNA prime provokes a comprehensive T cell response consisting of circulating and lung TRM after the boost, while the plasmid DNA prime induces mostly mucosal T cells. Concomitantly, the intranasal boost strategies lead to complete protection against a SARS-CoV-2 infection in mice. Our data thus suggest that mucosal booster immunizations after mRNA priming is a promising approach to establish mucosal immunity in addition to systemic responses

Rational design of N-heterocyclic compound classes via regenerative cyclization of diamines

Introducing unknown compound classes is the key to extent the chemical space qualitatively. Here the authors report on a concept to design heterocyclic compound classes rationally and the synthesis of unknown classes of N-heterocyclic compound

Sterically demanding iminopyridine ligands

Two sterically demanding iminopyridine ligands, (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridin-2-ylmeth- ylene]amine and (2,6-diisopropylphenyl)]6-(2,6-dimethylphenyl)pyridin-2-ylmethylene]amine, were prepared by a two-step process: first, condensation of 6-bromopyridine-2-carbaldehyde with an equimolecular amount of 2,6-diisopropylaniline, and second, Kumada-type coupling of in-situ-formed Grignard compounds of 1-bromo-2,6-dimethylphenyl and 1-bromo-2,4,6-triisopropylphenyl. Dichlorido complexes of the ligands were synthesized starting from FeCl2, [PdCl2(cod)], [NiCl2(dme)], and CoCl2 (cod = 1,5-cyclooctadiene, dine = dimethoxyethane). X-ray crystal structure analyses of a Fe, Pd, and Co complex were determined. Ethylene polymerization/oligomerization behavior of the dichlorido complexes after activation with methyl duminoxane or triethylaluminum was studied. Ethylene dimerization selectivity greater than 95% was observed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007

CCDC 639684: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 639685: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 639686: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.