Immunoglobulin fragment F(ab’)₂against RBD potently neutralizes SARS-CoV-2 in vitro

Abstract

COVID-19 caused by the emerging human coronavirus, SARS-CoV-2, has become a global pandemic, leading a serious threat to human health. So far, there is none vaccines or specific antiviral drugs approved for that. Therapeutic antibodies for SARS-CoV-2, was obtained from hyper immune equine plasma in this study. Herein, SARS-CoV-2 RBD with gram level were obtained through Chinese hamster ovary cells high-density fermentation. The binding of RBD to SARS-CoV-2 receptor, human ACE2, was verified and the efficacy of RBD in vivo was tested on mice and then on horses. As a result, RBD triggered high-titer neutralizing antibodies in vivo, and immunoglobulin fragment F(ab')2 was prepared from horse antisera through removing Fc. Neutralization test demonstrated that RBD-specific F(ab')2 inhibited SARS-CoV-2 with EC50 at 0.07 μg/ml, showing a potent inhibitory effect on SARS-CoV-2. These results highlights as RBD-specific F(ab')2 as therapeutic candidate for SARS-CoV-2.

Neutralizing antibodies targeting SARS-CoV-2 spike protein

“…Then F(ab′)2 fragment was harvested by removal of equine Fc instead of fusion to human Fc. In vivo results in mouse and horse showed inhibitory effects on SARS-CoV-2 with EC 50 at 0.07 μg/mL and EC 80 at 0.18 μg/mL ( Pan et al, 2020 ).…”

The construction, expression, and enhanced anti-tumor activity of YM101: a bispecific antibody simultaneously targeting TGF-β and PD-L1

“…The prepared YM101 was analyzed using SDS-PAGE and Coomassie Brilliant Blue staining. To verify the purity and molecular weight of YM101, reduced and non-reduced SDS-PAGE were conducted as previously described [47]. After Coomassie Brilliant Blue staining and decolorization, the images of the SDS-PAGE gels were captured with ChemiDoc MP Imaging system (Bio-Rad).…”

Clinically relevant cell culture models and their significance in isolation, pathogenesis, vaccine development, repurposing and screening of new drugs for SARS-CoV-2: a systematic review

“…Vero E6 or Vero 1008 cell line is the clone of Vero 76 cells and is a better option than Vero cells as it shows some contact inhibition and imitates properties more like primary cells. Immediately after the outbreak of SARS-CoV-2, several scientific groups used Vero and Vero E6 cells for their identification, pathogenesis as well as transmission studies ( Hoffmann et al, 2020 ; Chan et al, 2020b ; Zhou et al, 2020 ; Matsuyama et al, 2020 ),isolation ( Chan et al, 2020b ; Xiao et al, 2020 ; Caly et al, 2020a ; TT-Y et al, 2020 ; Harcourt et al, 2020 ; Chan et al, 2020c ; Capobianchi et al, 2020 ; Nie et al, 2020 ), and virus susceptibility ( Thevarajan et al, 2020 ).Vero and Vero E6 cell lines are used for the immune response ( Pan et al, 2020 ; Fukushi et al, 2006 ; Zheng et al, 2020 ), antibodies production ( Pu et al, 2020 ), vaccine production ( Mantlo et al, 2020 ), Type I IFNs as a target of antiviral therapy ( Anderson et al, 2020 ), MTHFD1 as a target of Antiviral Therapy ( Xing et al, 2020 ), virus-induced genes expression reversal ( Xiong et al, 2020a ), and mAbs screening ( Fintelman-Rodrigues et al, 2020 ). Vero cells were found to be the best screening models for new drugs as well as for already available anti-viral drugs for their repositioning as shown in Table 1 ( Xiong et al, 2020a ; Ge et al, 2020 ; Weston et al, 2020 ; Yao et al, 2020 ; Touret et al, 2020 ; Choy et al, 2020 ; Liu et al, 2020a ; Jin et al, 2020 ; Dai et al, 2020 ; Liu et al, 2020b ; Zhijian et al, 2020 ; Xiong et al, 2020b ; Wang et al, 2020a ; Caly et al, 2020b ; Sheahan et al, 2020a ; Runfeng et al, 2020 ; Andreani et al, 2020 ; Su et al, 2020 ;…”

“…Other kidney-specific cell lines used for SARS-CoV-2 study include LLC-MK2 for virus susceptibility ( Chan et al, 2013 ); MDCKII cell line for the screening of DHODH Inhibitors ( Wang et al, 2020a ), virus susceptibility ( Pan et al, 2020 ), and viral pathogenesis and transmission ( Hoffmann et al, 2020 );BHK-21 cell line for MAbs screening ( Fintelman-Rodrigues et al, 2020 );COS-7 cells for antibodies production ( Pu et al, 2020 ); PaKi cell line for MTHFD1 as a target of Antiviral Therapy ( Xing et al, 2020 ); and HK2 as well as NRK-49 F cell lines for Remdesivir drug screening ( Hamming et al, 2004 ).…”