Dynamics of humoral and cellular immune responses after homologous and heterologous SARS-CoV-2 vaccination with ChAdOx1 nCoV-19 and BNT162b2.

Background: Vaccines are an important means to overcome the SARS-CoV-2 pandemic. They induce specific antibody and T-cell responses but it remains open how well vaccine-induced immunity is preserved over time following homologous and heterologous immunization regimens. Here, we compared the dynamics of humoral and cellular immune responses up to 180 days after homologous or heterologous vaccination with either ChAdOx1-nCoV-19 (ChAd) or BNT162b2 (BNT) or both.

Three exposures to the spike protein of SARS-CoV-2 by either infection or vaccination elicit superior neutralizing immunity to all variants of concern.

Infection-neutralizing antibody responses after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or coronavirus disease 2019 vaccination are an essential component of antiviral immunity. Antibody-mediated protection is challenged by the emergence of SARS-CoV-2 variants of concern (VoCs) with immune escape properties, such as omicron (B.1.

Dynamics of spike-and nucleocapsid specific immunity during long-term follow-up and vaccination of SARS-CoV-2 convalescents.

Anti-viral immunity continuously declines over time after SARS-CoV-2 infection. Here, we characterize the dynamics of anti-viral immunity during long-term follow-up and after BNT162b2 mRNA-vaccination in convalescents after asymptomatic or mild SARS-CoV-2 infection. Virus-specific and virus-neutralizing antibody titers rapidly declined in convalescents over 9 months after infection, whereas virus-specific cytokine-producing polyfunctional T cells persisted, among which IL-2-producing T cells correlated with virus-neutralizing antibody titers.

Spiroconjugation in spirodicorrolato-dinickel(II).

In the present work the effect of spiroconjugation on the electronic spectrum of the recently synthesized metal complex hexadecaethylspirodicorrolato-dinickel(II) (5) (the corrole units in 5 are isoforms) is investigated. To have a suitable reference compound at our disposal, tetraethylhexamethylisocorrolato nickel(II) (7) has been prepared. On comparing the electronic spectra of this reference compound and the spiro-complex, bathochromic shifts of all absorption bands in the NIR/Vis-region are observed for the latter as well as marked changes in the spectral intensities.

Metal complexes of porphycene, corrphycene, and hemiporphycene: stability and coordination chemistry.

Porphyrin (P), porphycene (Pc), corrphycene (Cn), and hemiporphycene (Hpc) represent a series of well defined "4-N in" constitutional porphyrin isomers. These isomers, in the form of their octaethyl derivatives, represent a congruent set of porphyrinoids whose properties can be compared. In this study we report how variations in electronic structure and nitrogen-core size in the free-base forms of these four systems are reflected in the properties of their corresponding metal complexes.

Five-coordinate iron(III) porphycenes: (1)H NMR, magnetic, and structural studies.

Five-coordinate iron(III) 2,7,12,17-tetrapropylporphycene (TPrPc)Fe(III)X (X = C(6)H(5)O(-), Cl(-), Br(-), I(-), ClO(4)(-)) complexes have been investigated. The (1)H NMR spectra demonstrate downfield shifts for pyrrole resonances [(TPrPc)Fe(III)(C(6)H(5)O), 65.3 ppm; (TPrPc)Fe(III)Cl, 28.

Synthesis and Electrochemistry of Tin(IV) Octaethylcorroles, (OEC)Sn(C(6)H(5)) and (OEC)SnCl.

Two Sn(IV) corroles were synthesized and electrochemically examined. The investigated compounds are represented as (OEC)Sn(C(6)H(5)) and (OEC)SnCl, where OEC = trianion of 2,3,7,8,12,13,17,18-octaethylcorrole. (OEC)Sn(C(6)H(5)) represents the first example of a sigma-bonded metallocorrole which does not undergo a metal-centered electrode reaction.

X-Ray Photoelectron Spectroscopy of Porphycenes: Charge Asymmetry Across Low-Barrier Hydrogen Bonds.

It is ironic that although it is typically a technique that "sees" all elements other than hydrogen atoms, X-ray photoelectron spectroscopy (XPS) acts as a sensitive probe of low-barrier hydrogen bonds, as seen in a study of free-base tetrapyrroles. The nitrogen 1s XPS peaks never quite coalesce, even when the N⋅⋅⋅H⋅⋅⋅N hydrogen bonds are almost perfectly symmetrical, as is the case for dibenzo[cde,mno]porphycenes.

Synthesis, Characterization, and Electrochemistry of sigma-Bonded Cobalt Corroles in High Oxidation States.

The synthesis, electrochemistry, spectroscopy, and structural characterization of two high-valent phenyl sigma-bonded cobalt corroles containing a central cobalt ion in formal +IV and +V oxidation states is presented. The characterized compounds are represented as phenyl sigma-bonded cobalt corroles, (OEC)Co(C(6)H(5)) and [(OEC)Co(C(6)H(5))]ClO(4), where OEC is the trianion of 2,3,7,8,12,13,17,18-octaethylcorrole. The electronic distribution in both molecules is discussed in terms of their NMR and EPR spectroscopic data, magnetic susceptibility, and electrochemistry.

Electrochemical and Spectral Characterization of Iron Corroles in High and Low Oxidation States: First Structural Characterization of an Iron(IV) Tetrapyrrole π Cation Radical.

The electrochemistry and spectroscopic properties of three iron corroles were examined in benzonitrile, dichloromethane, and pyridine containing 0.1 M tetra-n-butylammonium perchlorate or tetra-n-ethylammonium hexafluorophosphate as supporting electrolyte. The investigated compounds are represented as (OEC)Fe(CH), (OEC)FeCl, and (OEC)Fe(py), where OEC is the trianion of 2,3,7,8,12,13,17,18-octaethylcorrole.

Electrochemical and Spectral Characterization of Iron Corroles in High and Low Oxidation States: First Structural Characterization of an Iron(IV) Tetrapyrrole pi Cation Radical.

The electrochemistry and spectroscopic properties of three iron corroles were examined in benzonitrile, dichloromethane, and pyridine containing 0.1 M tetra-n-butylammonium perchlorate or tetra-n-ethylammonium hexafluorophosphate as supporting electrolyte. The investigated compounds are represented as (OEC)Fe(IV)(C(6)H(5)), (OEC)Fe(IV)Cl, and (OEC)Fe(III)(py), where OEC is the trianion of 2,3,7,8,12,13,17,18-octaethylcorrole.