Abstract: The present disclosure an ELISA-based assay that uses a glycosylated polypeptide fragment derived from the SARS-CoV-2 spike protein (Covid-19) receptor binding domain (S1RBD) that has affinity for the extracellular domain of Angiotensin Converting Enzyme 2 (ACE2). The S1RBD polypeptide is generated by expression of an encoding nucleic acid by a human cell expression system resulting in glycosylation of the expressed spike receptor binding domain (S1RBD) protein at least at the N343 N-glycosylation site thereof, and which surprisingly and significantly increases the affinity of the S1RBD for ACE2, provides a significant increase in the sensitivity of the assay compared to other known assays.

Abstract: The present disclosure an ELISA-based assay that uses a glycosylated polypeptide fragment derived from the SARS-CoV-2 spike protein (Covid-19) receptor binding domain (S1RBD) that has affinity for the extracellular domain of Angiotensin Converting Enzyme 2 (ACE2). The S1RBD polypeptide is generated by expression of an encoding nucleic acid by a human cell expression system resulting in glycosylation of the expressed spike receptor binding domain (S1RBD) protein at least at the N343 N-glycosylation site thereof, and which surprisingly and significantly increases the affinity of the S1RBD for ACE2, provides a significant increase in the sensitivity of the assay compared to other known assays.

Abstract: The present disclosure an ELISA-based assay that uses a glycosylated s1F polypeptide fragment derived from the SARS-CoV-2 spike protein (Covid-19) spike protein, the N-terminal domain of which has affinity for the tyrosine-protein kinase receptor UFO (AXL). The S1F polypeptide can be generated by expression of an encoding nucleic acid by a human cell expression system resulting in glycosylation of the expressed S1F polypeptide at least at the N343 N-glycosylation site thereof, and which surprisingly and significantly increases the affinity of the S1F for AXL, provides a significant increase in the sensitivity of the assay compared to other known assays. Further the AXL polypeptide can be glycosylated, which further increases the affinity for S1F and AXL to each other.

Abstract: The present disclosure an ELISA-based assay that uses a glycosylated polypeptide fragment derived from the SARS-CoV-2 spike protein (Covid-19) receptor binding domain (S1RBD) that has affinity for the extracellular domain of Angiotensin Converting Enzyme 2 (ACE2). The S1RBD polypeptide is generated by expression of an encoding nucleic acid by a human cell expression system resulting in glycosylation of the expressed spike receptor binding domain (S1RBD) protein at least at the N343 N-glycosylation site thereof, and which surprisingly and significantly increases the affinity of the S1RBD for ACE2, provides a significant increase in the sensitivity of the assay compared to other known assays.

Abstract: Provided are embodiments of a method for determining a serum protein biomarker profile of a subject patient comprising: wicking blood from a subject onto a fluid sample collecting comb consisting of absorbent strips, each absorbent strip consisting of a fibrous absorbent wick configured to absorb a predetermined volume of blood; drying the blood samples on the wicks and eluting serum proteins into an elution buffer; determining the identities and levels of the extracted proteins by microarray analysis; comparing by computer the identities and levels of the extracted proteins with a reference database generated from the blood samples from a plurality of subjects collected by a fluid sample collecting comb and producing a computer-generated report of the identities and levels of the biomarkers of the subject and adjusting the treatment based on the identities and amounts of the protein biomarkers of the blood sample of the subject.