SARS-CoV-2-Specific Adaptive Immunity in COVID-19 Survivors With Asthma

BackgroundAsthma patients potentially have impaired adaptive immunity to virus infection. The levels of SARS-CoV-2-specific adaptive immunity between COVID-19 survivors with and without asthma are presently unclear.MethodsCOVID-19 survivors (patients with asthma n=11, with allergies n=8, and COVID-19 only n=17) and non-COVID-19 individuals (asthmatic patients n=10 and healthy controls n=9) were included. The COVID-19 patients were followed up at about 8 months and 16 months after discharge. The clinical characteristics, lymphocyte subsets, memory T cells, and humoral immunity including SARS-CoV-2 specific antibodies, SARS-CoV-2 pseudotyped virus neutralization assay, and memory B cells were analyzed in these subjects.ResultsThe strength of virus-specific T cell response in COVID-19 survivors was positively correlated with the percentage of blood eosinophils and Treg cells (r=0.4007, p=0.0188; and r=0.4435, p=0.0086 respectively) at 8-month follow-up. There were no statistical differences in the levels of SARS-CoV-2-specific T cell response between the COVID-19 survivors with, and without, asthma. Compared to those without asthma, the COVID-19 with asthma survivors had higher levels of SARS-CoV-2-specific neutralizing antibodies (NAbs) at the 8-month follow-up (p<0.05). Moreover, the level of NAbs in COVID-19 survivors was positively correlated with the percentage of Treg and cTfh2 cells (r=0.5037, p=0.002; and r=0.4846, p=0.0141), and negatively correlated with the percentage of Th1 and Th17 cells (r=-0.5701, p=0.0003; and r=-0.3656, p=0.0308), the ratio of Th1/Th2, Th17/Treg, and cTfh1/cTfh2 cell (r=-0.5356, r=-0.5947, r=-0.4485; all p<0.05). The decay rate of NAbs in the COVID-19 survivors with asthma was not significantly different from that of those without asthma at 16-month follow-up.ConclusionThe level of SARS-CoV-2-specific NAbs in COVID-19 survivors with asthma was higher than that of those without asthma at 8-month follow-up. The SARS-CoV-2-specific T cell immunity was associated with blood eosinophils and Treg percentages. The SARS-CoV-2-specific humoral immunity was closely associated with cTfh2/cTfh1 imbalance and Treg/Th17 ratio. According to the findings, asthmatic patients in COVID-19 convalescent period may benefit from an enhanced specific humoral immunity, which associates with skewed Th2/Th1 and Treg/Th17 immune

A Preliminary Study on the Domestication and Breeding Methods of Experimental Cats

ObjectiveFocused on the laboratory animal domestication and breeding of domestic cats, to explore the feeding management methods and breeding techniques of experimental cats.MethodsSeven Chinese garden cats from three litters were introduced from the rural suburbs of Guangzhou, and a breeding seed colony was established. The cats were domesticated in captivity, bred, closed breeding and transmission according to the feeding and management methods of laboratory animal. The population reproduction, the number of pregnancies per year, the litter season, the birth and weaning quality of the cats, and the survival rate of weaning were statistically collected.ResultsThe young breeding cats were able to adapt to the cage feeding management. In the transmission breeding and the expanded breeding colony, the number of female cats pregnant with one, two or three litters a year accounted for 63.2%, 26.3% and 10.5%, respectively. The proportions of litters born from the 1st to the 4th quarters were 20.7%, 20.7%, 27.6%, and 31.0%. A total of 29 pregnancies and 101 kittens were got from 19 female cats, with an average of (3.5±1.33) kittens per litter. The birth weights of female and male cats were (89.31±13.69) g and (93.47±15.12) g, respectively. Sixty-seven kittens survived from weaning. The average survival rate was 60.86%, and the weaning weights of female and male cats were (361.62±82.77) g and (376.0±91.71) g, respectively.ConclusionDomestic Chinese garden cats can adapt to laboratory animal feeding and breeding rules, and have strong fertility. They can normally pregnant and breeding throughout the year. The kittens grow to 5-6 months of age can meet the weight requirements for the examination of pharmaceutical hypotensive substances, and can be used as experimental cats for pharmaceutical examination with clear origin

Phase transition, domain structure and electrical properties of Mn-doped 0.3 Pb(In1/2Nb1/2)O3-0.4 Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 crystals

The 0.5 mol.% Mn-doped 0.3 Pb(In1/2Nb1/2)O3-0.4 Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (Mn-PIMNT) single crystal was grown by a modified Bridgman technology. A comprehensive study involving the electrical properties, as well as phase transitions and domain configuration behavior of (001)-oriented Mn-PIMNT single crystal has been carried out. Three anomalies around 115 °C (TR-M), 122 °C (TM-T), 155 °C (TT-C) were observed in dielectric performance analysis, and their dielectric constant exhibited strong frequency dependence. The strain curves showed that the phase transitions at high temperatures induced by electric field were discontinuous, reflecting the characteristics of first-order-like phase transitions. Furthermore, the temperature related converse piezoelectric constant (d33), coercive field (Ec), remnant polarization (Pr), maximum strain (Smax) and longitudinal electrostrictive coefficient (Q) showed diverse variation trend. The values of Pr and Ec gradually decreased as the temperature rose, and when the temperature approached to TR-M and TM-T, values of Pr decreased while values of Smax and Q increased dramatically. The fatigue test of this single crystal showed almost fatigue-free behavior even after 1 × 105 cycles. The results of temperature-dependent PFM tests demonstrated the great temperature stability of the Mn-PIMNT single crystal, which makes it possible for application in high-temperature devices. © 2019 Elsevier B.V

PD-1-Targeted Discovery of Peptide Inhibitors by Virtual Screening, Molecular Dynamics Simulation, and Surface Plasmon Resonance

The blockade of the programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) pathway plays a critical role in cancer immunotherapy by reducing the immune escape. Five monoclonal antibodies that antagonized PD-1/PD-L1 interaction have been approved by the Food and Drug Administration (FDA) and marketed as immunotherapy for cancer treatment. However, some weaknesses of antibodies, such as high cost, low stability, poor amenability for oral administration, and immunogenicity, should not be overlooked. To overcome these disadvantages, small-molecule inhibitors targeting PD-L1 were developed. In the present work, we applied in silico and in vitro approaches to develop short peptides targeting PD-1 as chemical probes for the inhibition of PD-1–PD-L1 interaction. We first predicted the potential binding pocket on PD-1/PD-L1 protein–protein interface (PPI). Sequentially, we carried out virtual screening against our in-house peptide library to identify potential ligands. WANG-003, WANG-004, and WANG-005, three of our in-house peptides, were predicted to bind to PD-1 with promising docking scores. Next, we conducted molecular docking and molecular dynamics (MD) simulation for the further analysis of interactions between our peptides and PD-1. Finally, we evaluated the affinity between peptides and PD-1 by surface plasmon resonance (SPR) binding technology. The present study provides a new perspective for the development of PD-1 inhibitors that disrupt PD-1–PD-L1 interactions. These promising peptides have the potential to be utilized as a novel chemical probe for further studies, as well as providing a foundation for further designs of potent small-molecule inhibitors targeting PD-1

Treg cell-derived osteopontin promotes microglia-mediated white matter repair after ischemic stroke

The precise mechanisms underlying the beneficial effects of regulatory T (Treg) cells on long-term tissue repair remain elusive. Here, using single-cell RNA sequencing and flow cytometry, we found that Treg cells infiltrated the brain 1 to 5 weeks after experimental stroke in mice. Selective depletion of Treg cells diminished oligodendrogenesis, white matter repair, and functional recovery after stroke. Transcriptomic analyses revealed potent immunomodulatory effects of brain-infiltrating Treg cells on other immune cells, including monocyte-lineage cells. Microglia depletion, but not T cell lymphopenia, mitigated the beneficial effects of transferred Treg cells on white matter regeneration. Mechanistically, Treg cell-derived osteopontin acted through integrin receptors on microglia to enhance microglial reparative activity, consequently promoting oligodendrogenesis and white matter repair. Increasing Treg cell numbers by delivering IL-2:IL-2 antibody complexes after stroke improved white matter integrity and rescued neurological functions over the long term. These findings reveal Treg cells as a neurorestorative target for stroke recovery