Gd endohedral complexes of C82 fullerenols were synthesized and mass spectrometry analysis of their composition was carried out. It was established that the synthesis yields a series of fullerenols ...Gd@C82Ox(OH)y (x = 0, 3; y = 8, 16, 24, 36, 44). The atomic and electronic structure and properties of the synthesized fullerenols were investigated using the density functional theory calculations. It was shown that the presence of endohedral gadolinium increases the reactivity of fullerenols. It is proposed that the high-spin endohedral fullerenols are promising candidates for application in magnetic resonance imaging.
Herein, a novel pH‐responsive phosphorescent probe based on cyclometalated iridium(III) complex is reported. To prevent oxygen quenching of phosphorescence and to improve the probe biocompatibility, ...the complex is covalently conjugated with a water‐soluble block‐copolymer that also increases its pH sensitivity. The resulting polymeric nanoprobe demonstrates a strong response of the phosphorescence lifetime onto pH variations in physiological range. Cellular experiments with Chinese hamster ovary (CHO‐K1) cells show the predominant internalization of the probe in acidified cell compartments, endosomes and lysosomes. The analysis of phosphorescence lifetime imaging microscopy data confirms applicability of the sensor for monitoring of intra‐ and extracellular pH in cell cultures.
The pH‐sensitive phosphorescent Ir(III) complex is successfully inserted into the polymeric shell to prevent oxygen dependence of its emission parameters and enhance biocompatibility. The resulting nanoprobe is easily internalized into endosomes and lysosomes of Chinese hamster ovary (CHO‐K1 cells). Phosphorescence lifetime imaging experiments on cells clearly show that the probe allows differentiation of individual vesicles from the viewpoint of their acidity.
Three novel luminescent Eu(III) complexes,
-
, have been synthesized and characterized with CHN analysis, mass-spectrometry and
H NMR spectroscopy. The complexes display strong emission in ...dichloromethane solution upon excitation at 405 and 800 nm with a quantum yield from 18.3 to 31.6%, excited-state lifetimes in the range of 243-1016 ms at 20 °C, and lifetime temperature sensitivity of 0.9%/K (
), 1.9%/K (
), and 1.7%/K (
). The chromophores were embedded into biocompatible latex nanoparticles (
-
) that prevented emission quenching and kept the photophysical characteristics of emitters unchanged with the highest temperature sensitivity of 1.3%/K (
). For this probe cytotoxicity, internalization dynamics and localization in CHO-K1 cells were studied together with lifetime vs. temperature calibration in aqueous solution, phosphate buffer, and in a mixture of growth media and fetal bovine serum. The obtained data were then averaged to give the calibration curve, which was further used for temperature estimation in biological samples. The probe was stable in physiological media and displayed good reproducibility in cycling experiments between 20 and 40 °C. PLIM experiments with thermostated CHO-K1 cells incubated with
indicated that the probe could be used for temperature estimation in cells including the assessment of temperature variations upon chemical shock (sample treatment with mitochondrial uncoupling reagent).
Understanding the hallmarks of the immune response to SARS-CoV-2 is critical for fighting the COVID-19 pandemic. We assessed antibody and T cell reactivity in convalescent COVID-19 patients and ...healthy donors sampled both prior to and during the pandemic. Healthy donors examined during the pandemic exhibited increased numbers of SARS-CoV-2-specific T cells, but no humoral response. Their probable exposure to the virus resulted in either asymptomatic infection without antibody secretion or activation of preexisting immunity. In convalescent patients, we observed a public and diverse T cell response to SARS-CoV-2 epitopes, revealing T cell receptor (TCR) motifs with germline-encoded features. Bulk CD4+ and CD8+ T cell responses to the spike protein were mediated by groups of homologous TCRs, some of them shared across multiple donors. Overall, our results demonstrate that the T cell response to SARS-CoV-2, including the identified set of TCRs, can serve as a useful biomarker for surveying antiviral immunity.
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•Healthy donors sampled in 2020 had an increased T cell response to SARS-CoV-2•SARS-CoV-2 glycoprotein S-specific TCR repertoire features public CDR3 motifs•Two epitopes are recognized by the majority of the HLA-A2+ COVID-19 convalescents
Shomuradova et al. assessed the immune response to SARS-CoV-2 in convalescent patients and healthy donors. Antigen-specific T cells were increased in convalescents and in donors sampled during the pandemic. The work identified two public epitopes from S-glycoprotein. T cell receptor repertoire profiling of S-glycoprotein-specific lymphocytes revealed public CDR3 motifs.
A series of diphosphine Re(I) complexes
-
have been designed via decoration of the archetypal core {Re(CO)
(N^N)} through the installations of the phosphines
and
bearing the terminal double bond, ...where N^N = 2,2'-bipyridine (
), 4,4'-di-tert-butyl-2,2'-bipyridine (
) or 2,9-dimethyl-1,10-phenanthroline (
) and
= diphenylvinylphosphine, and
= 4-(diphenylphosphino)styrene. These complexes were copolymerized with the corresponding N-vinylpyrrolidone-based Macro-RAFT agents of different polymer chain lengths to give water-soluble copolymers of low-molecular
) and high-molecular
block-copolymers containing rhenium complexes. Compounds
-
, as well as the copolymers
and
, demonstrate phosphorescence from a
MLCT excited state typical for this type of chromophores. The copolymers
and
display weak sensitivity to molecular oxygen in aqueous and buffered media, which becomes almost negligible in the model physiological media. In cell experiments with CHO-K1 cell line,
and
displayed significantly reduced toxicity compared to the initial
complex and internalized into cells presumably by endocytic pathways, being eventually accumulated in endosomes. The sensitivity of the copolymers to oxygen examined in CHO-K1 cells via phosphorescence lifetime imaging microscopy (PLIM) proved to be inessential.
Five square‐planar Pt(C^N*N′^C′) complexes (Pt1–Pt5) with novel nonsymmetric tetradentate ligands (L1–L5) were synthesized and characterized. Varying the structure of the metalating aromatic systems ...result in substantial changes in photophysical properties and intermolecular interaction mode of the complexes in solution and in solid state. The complexes are strongly emissive in tetrahydrofuran solution, with the band maxima ranging from 560 to 690 nm. Three of these complexes (Pt1, Pt2, Pt4) afford nanospecies upon injection of their solution into water, which show aggregation‐induced emission (AIE) with a strong red shift of emission bands. In the solid state, crystalline samples of these complexes demonstrate mechanochromism upon grinding with a bathochromic shift of the emission. DFT and TD‐DFT computational analysis of monomeric Pt1–Pt5 in solution and model dimeric emitters formed through intermolecular interaction of Pt1, Pt2, Pt4 molecules allowed assignment of observed AIE to the 3MMLCT excited states of Pt‐Pt bonded aggregates of these complexes.
Square‐planar PtII complexes with tetradentate nonsymmetric {C^N*N′^C′} ligands display aggregation‐induced emission (AIE) in the solid state and in nanoparticles formed upon mixing of their solutions in THF with water. The ability of the complexes to show AIE is determined by the steric and electronic properties of the ligands’ aromatic systems.
Invited for the cover of this issue are the groups of Sergey P. Tunik and his colleagues from St Petersburg University. The image depicts the strong bathochromic shift of the emission wavelength of ...phosphorescent platinum(II) complexes upon their aggregation in the presence of water. Read the full text of the article at 10.1002/chem.202202207.
“The relatively simple technology of nanospecies preparation affords chromophores with NIR emission particularly suitable for application in biomedical studies.” This and more about the story behind the front cover can be found in the article at 10.1002/chem.202202207).
Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease of unknown etiology. Genetic predisposition and dysbiotic gut microbiota are important factors in the pathogenesis of CD. In ...this study, we analyzed the taxonomic composition of the gut microbiota and genotypes of 24 single nucleotide polymorphisms (SNP) associated with the risk of CD. The studied cohorts included 96 CD patients and 24 healthy volunteers from Russia. Statistically significant differences were found in the allele frequencies for 8 SNPs and taxonomic composition of the gut microbiota in CD patients compared with controls. In addition, two types of gut microbiota communities were identified in CD patients. The main distinguishing driver of bacterial families for the first community type are
and unclassified members of the
order, and the second type is characterized by increased abundance of
and
. Differences in the allele frequencies of the rs9858542 (
), rs3816769 (
), and rs1793004 (
) were also found between groups of CD patients with different types of microbiota communities. These findings confirm the complex multifactorial nature of CD.
In a prospective study involving 5340 individuals, humoral and cellular responses revealed magnitude-dependent protection from COVID-19. Antibodies alone significantly decreased infection rates; ...isolated cellular response provided an intermediate level of protection. The lowest COVID-19 incidence was in the double-positive group.
Abstract
Background
During the ongoing coronavirus disease 2019 (COVID-19) pandemic, many individuals were infected with and have cleared the virus, developing virus-specific antibodies and effector/memory T cells. An important unanswered question is what levels of T-cell and antibody responses are sufficient to protect from the infection.
Methods
In 5340 Moscow residents, we evaluated anti–severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin M (IgM)/immunoglobulin G (IgG) titers and frequencies of the T cells specific to the membrane, nucleocapsid, and spike proteins of SARS-CoV-2, using interferon gamma (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) assay. Additionally, we evaluated the fractions of virus-specific CD4+ and CD8+ T cells using intracellular staining of IFN-γ and interleukin 2 followed by flow cytometry. We analyzed the COVID-19 rates as a function of the assessed antibody and T-cell responses, using the Kaplan–Meier estimator method, for up to 300 days postinclusion.
Results
We showed that T-cell and antibody responses are closely interconnected and are commonly induced concurrently. Magnitudes of both responses inversely correlated with infection probability. Individuals positive for both responses demonstrated the highest levels of protectivity against the SARS-CoV-2 infection. A comparable level of protection was found in individuals with antibody response only, whereas the T-cell response by itself granted only intermediate protection.
Conclusions
We found that the contribution of the virus-specific antibodies to protection against SARS-CoV-2 infection is more pronounced than that of the T cells. The data on the virus-specific IgG titers may be instructive for making decisions in personalized healthcare and public anti–COVID-19 policies.
Clinical Trials Registration. NCT04898140.
Square‐planar Pt(C^N*N′^C′) complexes bearing novel nonsymmetric tetradentate ligands display strong green‐yellow emission in their monomeric form in tetrahydrofuran solution. Mixing the THF ...solutions with water results in aggregation of the complexes to afford nanospecies with clearly visible aggregation‐induced emission (AIE) that shifts the luminescent bands to the near infrared due to a metallophilic interaction between the starting molecular chromophores. More information can be found in the Research Article by S. P. Tunik and co‐workers (DOI: 10.1002/chem.202202207).
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