RESUMEN
SARS-CoV-2 unprecedentedly threatens the public health at worldwide level. There is an urgent need to develop an effective vaccine within a highly accelerated time. Here, we present the most comprehensive S-protein-based linear B-cell epitope candidate list by combining epitopes predicted by eight widely-used immune-informatics methods with the epitopes curated from literature published between Feb 6, 2020 and July 10, 2020. We find four top prioritized linear B-cell epitopes in the hotspot regions of S protein can specifically bind with serum antibodies from horse, mouse, and monkey inoculated with different SARS-CoV-2 vaccine candidates or a patient recovering from COVID-19. The four linear B-cell epitopes can induce neutralizing antibodies against both pseudo and live SARS-CoV-2 virus in immunized wild-type BALB/c mice. This study suggests that the four linear B-cell epitopes are potentially important candidates for serological assay or vaccine development.
RESUMEN
BACKGROUND:Many scholars have experimental y confirmed the obvious effect of mesenchymal stem cells to repair radiation injury. OBJECTIVE:To preliminarily investigate the mechanism of human umbilical cord mesenchymal stem cells promoting the healing of combined radiation-wound skin injury and whether they possess tumorigenicity in vitro. METHODS:Fifteen Sprague-Dawley rats were randomly divided into three groups, five rats in each group. The right buttock of rats (2.5 cm×2.0 cm) was irradiated with 40 Gyβ-rays produced by a linear accelerator, in which a round wound with a diameter of 1.5 cm was made. After 12 hours of modeling, human umbilical cord mesenchymal stem cells at three concentrations (5.0×106, 1.0×107 and 2.0×107 ) were injected through tail vein of rats, and luciferin (20 mg/kg) was injected intraperitoneal y. celldistribution in vivo was traced using IVIS in vivo imaging system. The ability of human umbilical cord mesenchymal stem cells to form colonies was observed using the colony formation assay with soft agar. RESULTS AND CONCLUSION:Human umbilical cord mesenchymal stem cells injected through tail vein of rats were mostly gathered in the lungs. cells were accumulated in the injured site of rats injected with 2.0×10 7 human umbilical cord mesenchymal stem cells;however, the fluorescence signal was not observed in the injured site of rats injected with 5.0×106 and 1.0×107 human umbilical cord mesenchymal stem cells. The other results indicated human umbilical cord mesenchymal stem cells of low dose, medium dose and high dose had no colony formation on soft agar, but the tumor cells had a great ability to form colony. These findings indicate that human umbilical cord mesenchymal stem cells promote healing combined radiation-wound skin injury by local migration and exhibit no tumorigenicity in vitro in a short period.
