Journal: Viruses

Article Title: Antibody-Dependent Enhancement of SARS-CoV-2 Infection of Human Immune Cells: In Vitro Assessment Provides Insight in COVID-19 Pathogenesis

doi: 10.3390/v13122483

Figure Lengend Snippet: Convalescent sera from COVID-19 patients induced ADE in multiple peripheral blood immune cells. ( A ) UMAP show the overview of the population of SARS-CoV-2 RNA positive cells ( n = 1078), which were derived from BALF and two sputum samples of COVID-19 patients. Identification of cell population was corresponded to the description of a previous study . ( B ) Normalized expression of SARS-CoV-2 RNA in each virus positive cell. Data were reanalyzed from the published dataset . ( C ) Expression of different FcγRs including FcγRI, FcγRII, and FcγRIII on primary B cells, monocytes, or macrophages was detected by flow cytometry. ( D ) Quantification of FcγR expression by comparing the mean fluorescent intensity value. ( E ) SARS-CoV-2 virus pretreated with equal-volume convalescent sera from one COVID-19 patient or RPMI1640 medium at 37 °C for 30 min. Viral–serum mixtures were added to primary B cells, monocytes, and macrophages that were prepared from one healthy donor at a moi of 0.1. Samples were harvested at 48 h post infection and cellular viral load was then quantified by qRT-PCR detection targeting the viral receptor-binding domain (RBD). ( F ) SARS-CoV-2 virus was pretreated with equal-volume convalescent sera from two COVID-19 patients (RBD IgG OD values of 1.759 and 1.851, respectively) or RPMI1640 medium at 37 °C for 30 min. Viral–serum mixtures were added to primary B cells, monocytes, and macrophages from healthy donors at a moi of 0.1. Samples were harvested at 48 h post infection and cellular viral NP was then detected by flow cytometry. The data were analyzed using the Student’s t test and statistical significance is indicated (* p < 0.05; ** p < 0.01; *** p < 0.001; NS, no significance).

Article Snippet: Two microliters of RNA were used as a template for the amplification of selected genes by real-time quantitative PCR using HiSxript ® II One step qRT-PCR SYBR ® Green Kit. (Q221-01; Vazyme Biotech Co., Ltd, Nanjing, Jiangsu, China).

Techniques: Derivative Assay, Expressing, Virus, Flow Cytometry, Infection, Quantitative RT-PCR, Binding Assay

Journal: Viruses

Article Title: Antibody-Dependent Enhancement of SARS-CoV-2 Infection of Human Immune Cells: In Vitro Assessment Provides Insight in COVID-19 Pathogenesis

doi: 10.3390/v13122483

Figure Lengend Snippet: Factors related to ADE effect. ( A ) The expression of FcγRs in Raji B cells, a cloned immortalized cell line. ( B ) Raji B cells were infected with SARS-CoV-2 at a moi of 0.01, 0.1, and 0.2 with or without convalescent sera. Samples were harvested at 0 h, 24 h, or 48 h post infection and cellular viral load was then quantified by qRT-PCR detection of total viral RNA or subgenomic RNA (sgRNA). ( C ) SARS-CoV-2 virus pretreated with equal-volume convalescent sera from different COVID-19 patients (1:40 of final dilution) or RPMI1640 at 37 °C for 30 min. Viral mixtures were added to Raji B cells at a moi of 0.1. Samples were harvested at 48 h post infection and cellular viral load was then quantified by qRT-PCR detection of sgRNA. RBD IgG OD value and neutralizing titer of convalescent sera were quantified by ELISA or micro-neutralization assay, respectively. ( D ) Convalescent serum from one COVID-19 patient was diluted to 1:40, 1:80, 1:160, and 1:320. SARS-CoV-2 was pre-incubated with equal-volume sera at 37 °C for 30 min and then added to Vero E6 or Raji B cells at a moi of 0.1. Samples were harvested at 48 h post infection and cellular viral load was then quantified by qRT-PCR detection of viral RBD. The Vero E6 detection data can be found in . Comparison between different sample groups was analyzed by the Student’s t -test. * p <0.05; ** p < 0.01; *** p < 0.001; NS, no significance. The short lines mean to compare viral load in infected cells with or without patient sera).

Article Snippet: Two microliters of RNA were used as a template for the amplification of selected genes by real-time quantitative PCR using HiSxript ® II One step qRT-PCR SYBR ® Green Kit. (Q221-01; Vazyme Biotech Co., Ltd, Nanjing, Jiangsu, China).

Techniques: Expressing, Clone Assay, Infection, Quantitative RT-PCR, Virus, Enzyme-linked Immunosorbent Assay, Neutralization, Incubation, Comparison