As the Covid-19 pandemic progresses reliable antibodies to investigate the effects of SARS-CoV-2 in the human body become increasingly important. Two highly specific mouse monoclonal antibodies directed against the SARS-CoV-2 nucleocapsid protein show superior performance on FFPE tissue (IHC-P), IHC, ICC and in ELISA applications.
| mouse anti-SARS-CoV-2 nucleocapsid (clone 4A8) | mouse anti-SARS-CoV-1 and -2 nucleocapsid (clone 53E2) |
Figure 1: Immunohistochemical staining of formalin-fixed paraffin-embedded COVID-19 patient lung tissue or non-infected control lung using anti-SARS-CoV-2 (COVID-19) Nucleocapsid antibody (Clone 4A8, cat. no. HS-452 011, 1:1000 (A); Clone 53E2, cat. no. HS-452 111 1:500 (B)). Heat mediated antigen retrieval and staining was performed using the Ventana Benchmark XT autostainer; Scale bar: 100μm.*
* Immuno-histochemical sections of lung tissues were kindly tested and provided by Dres. Krasemann, Heinrich/Pfefferle, UKE-Hamburg/Germany.
Figure 2: Indirect immunostaining of PFA fixed mouse brain sections from K18-hACE2 transgenic mice infected with SARS-CoV-2 virus or non-infected using the monoclonal anti-SARS-CoV-2 nucleocapsid antibody clone 4A8 (cat. no. HS-452 011, dilution 1:1000; red) Nuclei have been visualized by DAPI staining (blue).
The mice were housed and infected at The Helmholtz Center for Infection research in cooperation with Prof. Kröger and Prof. Cicin-Sain.
| clone 4A8 recognizes exclusively SARS-CoV-2 | clone 53E2 recognizes SARS-CoV-1 and SARS-CoV-2 |
Figure 3: Immuno-histochemical staining of formalin fixed paraffin embedded HEK cells transfected with mammalian expression plasmids coding for full-length ALFA- or GFP tagged nucleo-capsid proteins of diverse coronavirus strains using the monoclonal anti-SARS-CoV-2 nucleocapsid antibody clone #4A8 (cat.no. HS-452 011, dilution 1:500, DAB). Nuclei have been counterstained with haematoxylin (blue). The anti-SARS-CoV-2 nucleocapsid antibody clone #4A8 is specific for the SARS-CoV-2 nucleocapsid protein and does not bind to nucleocapsid proteins of other coronavirus strains.
Figure 4: Immuno-histochemical staining of formalin fixed paraffin embedded HEK cells transfected with mammalian expression plasmids coding for full-length ALFA- or GFP tagged nucleo-capsid proteins of diverse coronavirus strains using the monoclonal anti-SARS-CoV-2 nucleocapsid antibody clone #53E2 (cat.no. HS-452 111, dilution 1:2000, DAB). Nuclei have been counterstained with haematoxylin (blue). The anti-SARS-CoV-2 nucleocapsid antibody clone 53E2 binds to SARS-CoV-1 and SARS-CoV-2 nucleocapsid proteins and does not bind to nucleocapsid proteins of other coronavirus strains.
Figure 5: Clones #4A8 and #53E2 were used in Sandwich ELISA settings to demonstrate the sensitivity of both antibodies. 50 ng/well of Clone #4A8 (cat.no. HS-452 011) was coated as capture antibody. Biotinylated clone #53E2 (cat.no. HS-452 111BT, 1:2000) was used as detection antibody. Streptavidin-HRP and TMB were used as development agents. Absorbance was detected at 405 nm. (A) Different concentrations of recombinant nucleocapsid protein (SARS-CoV-2) (50 ng/mL – 23.4 pg/mL) were tested in ELISA. X-axis in log 10 scale. (B) GFP tagged nucleocapsid protein (SARS-CoV-2) transfected HEK cells were FACS sorted. Different cell numbers of nucleocapsid protein (SARS-CoV-2) positive cells were lysed in 1% Triton X-100/PBS buffer and lysates were used in Sandwich ELISA to detect the nucleocapsid protein (SARS-CoV-2).
