Goat anti mouse igg h l fitc

To visualize cell infection, HeLa cells were seeded onto 24-well plates and infected with NDV at 0.1, 1, or 10MOI. At 24 and 48 hpi, cells were fixed with 4% paraformaldehyde, permeabilized with 0.25% Triton X-100, and blocked with 5% bovine serum albumin. Cells were then incubated with MAb-HN overnight at 4°C. The secondary antibody Goat Anti-Mouse IgG(H+L)-FITC (#1036–02, Southern Biotech) was incubated for 1 hour at room temperature. Nuclei were stained with hoechst (#14533, merck, USA). To visualize the fluorescence of Venus protein in the Bifc experiment, HeLa cells were seeded onto 24-well plates and transfected individually or co-transfected with the respective plasmids. After 18 hours, the cells were fixed using 4% paraformaldehyde, permeabilized with 0.25% Triton X-100, and nuclei were stained with hoechst.
Fluorescence images were captured using a Leica TCS SP8 fluorescence microscope (Leica Microsystems GmbH, Wetzlar, Germany). Then they were analyzed and merged using Adobe Photoshop 2020 software (Adobe Systems, San Jose, CA, USA). All experiments were repeated at least three times.

HEK293T cells were transfected with a plasmid DNA encoding SARS-CoV-2 spike protein once cells reached approximately 50–70% confluency using polyethylenimine. 24 hours post transfection, cells were rinsed with PBS then detached with EDTA. After cell counting, 5×10⁵ cells were washed with 1 mL PBFA (PBS supplemented with 2% fetal calf serum and 0.1% sodium azide) by resuspension and centrifugation at 800×g for 3 min at 4°C. The pellet was subsequently incubated in 100 μL primary antibody (sybodies at a final concentration of 3 μM or an equal volume of PBS; diluted in PBFA) at 4°C for 30 min. After washing in PBFA, cells were incubated in 100 μL of secondary antibody (1:100, Mouse anti-His-tag mAb, Abclonal, #AE003; then with Goat Anti-Mouse IgG(H+L)-FITC, SouthernBiotech, #1036–02; diluted in PBFA) at 4°C for 30 min and washed twice with 1 mL PBFA. 100,000 live cells in ice-cold PBS were analyzed by fluorescence-activated cell sorting (FACS). As a control group, the same amount of cells were also analyzed by FACS with no antibodies (sybodies and secondary antibodies).