Anti mouse igg taxes red conjugated antibody

SARS-CoV-2 S protein-expressing plasmids were transfected into HEK293T cells using Lipofectamine 3000 (Invitrogen, USA). 24 h after transfection, cells were suspended and washed with PBS twice. Then the cells were incubated with 20 μg/mL mAbs or isotype IgG mAb of hepatitis b virus (HBV), at room temperature for 1 h, followed by further incubation with anti-human IgG FITC-conjugated antibody (Sigma, USA). The cells were analyzed using FACSAria II (BD, USA). All of these data were analyzed using FlowJo.
The block assay was assessed by FACS. HEK293T cells were transiently transfected with the ACE2 expression plasmid for 24 h. The mouse-Fc tag Fusion protein of SARS-CoV-2 RBD (RBD-mFC) (Jiangsu East-Mab Biomedical Technology,China) at a concentration of 2 µg/mL was mixed with the mAbs or isotype IgG at a molar ratio of 1:10 and incubated at 4 °C for 1 h. Then mixtures were added to 2.5 × 10⁵ HEK293T cells expressing ACE2 and incubated at 4 °C for another hour. Then cells were stained with anti-mouse IgG Taxes red-conjugated antibody and anti-human IgG FITC-conjugated antibody (Sigma, USA) for another 30 min then analyzed by FACSAria II (BD, USA).