While traditional PCR-based assay remains as the golden standard for COVID-diagnosis, there is an increasing demand in other methods that enable quicker, easier, and more cost-effective tests. Lateral flow immunoassay (LFA) is an alternative platform that can be used to detect viral antigens in biological samples. Such tests rely on the availability of antibody pairs that can recognize the target antigen with desired specificity and sensitivity. Hundreds of antibodies against N and S proteins have been made available in recent months. Screening this large resource for a suitable pair has become a major speed limiting factor.

In a recent study supported by The Global Good Fund and Global Health Labs (created by Gates Ventures and the Gates Foundation), authors from Global Health Labs, Intellectual Ventures Laboratory, and PATH systematically evaluated all commercially available antibodies using a high throughput screening process directly on nitrocellulose. The study identified a dozen pairs with the best potential to deliver optimal results in LFA assays (Table 1).

Rank in clinical screenCapture antibodyDetection antibody
1Sino Biological, Cat-No. 40143-MM08Sino Biological, Cat-No. 40143-R004
2Sino Biological, Cat-No. 40143-MM05Sino Biological, Cat-No. 40143-MM08
3Sino Biological, Cat-No. 40143-MM08Sino Biological, Cat-No. 40143-MM05
4Creative Diagnostics, Cat-No. CABT-CS037Sino Biological, Cat-No. 40143-R004
5Genemedi GMP-V-2019nCoV-NAb001Sino Biological, Cat-No. 40143-MM08
6Bioss, Cat-No. bsm-41411MCreative Diagnostics, Cat-No. CABT-CS037
7Sino Biological, Cat-No. 40143-MM08Bioss, Cat-No. bsm-41412M
8Fitzgerald, Cat-No. 10-2856Bioss, Cat-No. bsm-41412M

Table 1: Antibody pairs selected to be screened against clinical samples are ranked according to average performance in the clinical screen.

Antibody Pairs for SARS-CoV-2 N Protein

Sino Biological has developed a large panel of antibodies against SARS-CoV-2 N protein. These pairs can be used to assemble detection assays for the corresponding antigen.

Antibody pairCapture antibodyDetection antibody
I40143-R00440143-R040
II40143-MM0540143-R001
III40143-MM0840143-R004

 

Antibodies Specific to SARS-CoV-2 Antigen

One of the main concerns for the antigen tests is whether the antibody pair also detects other circulating coronaviruses. To further validate the specificity, these antibodies were tested against a full panel of N proteins from the common coronaviruses. The result came back as all antibodies against the N proteins have no cross-reactivity in ELISA.

Cat-No.ItemSizePrice (CHF)
40588-R0004-100ulSARS-CoV-2 (2019-nCoV) Nucleocapsid Antibody, Rabbit MAb100 ul609.00

References

Cate et al., Antibody Screening Results for Anti-Nucleocapsid Antibodies Towards the Development of a SARS-CoV-2 Nucleocapsid Protein Antigen Detecting Lateral Flow Assay. ChemRxiv.2020 / https://doi.org/10.26434/chemrxiv.12709538.v1