For the detection of human anti-SARS-CoV-2 Nucleoprotein IgG antibodies.

The Human CD13 (ANPEP) ELISA kit is designed for the quantitative detection and measurement of human CD13 in biological fluids such as serum, plasma, and tissue homogenate. CD13, also known as aminopeptidase N or membrane alanyl aminopeptidase (ANPEP), is a type II membrane metalloprotease that consists of an extracellular-oriented catalytic domain.

CD13 regulates the activity of numerous hormones, cytokines, and chemokines in inflammation. It is also coexpressed by MHC class II (MHC II)-bearing antigen-presenting cells (APCs), and is involved in the trimming of MHC II-associated peptides on the surface of APCs. It is an important marker for acute myeloid leukaemia and plays a role in tumour invasion.

CD13 is also known to be involved in the final digestion of peptides generated from the hydrolysis of proteins by gastric and pancreatic proteases. Research suggests that CD13 is also involved in viral infection. It regulates the human cytomegalovirus and is a receptor for human coronavirus 229E (HCoV-229E) Spike glycoprotein in HCoV-229E infections. It is also a potential therapeutic target for numerous inflammatory disorders, including rheumatoid arthritis.

The assay is based on the sandwich ELISA method, in which samples are added to ELISA strip plates pre-coated with capture antibodies specific for CD13. The captured CD13 is detected by the addition of a biotinylated detection antibody, followed by streptavidin-horseradish peroxidase, which binds the biotinylated antibody.

Addition of the chromogenic enzyme substrate 3,3’, 5,5’ tetramethylbenzidine (TMB) results in a coloured product with an intensity directly proportional to the concentration of human CD13. The concentration of CD13 is determined by comparison to a serial dilution of the standard analysed in parallel.