Development of fragment-specific osteopontin antibodies and ELISA for quantification in human metastatic breast cancer

Table 3 Comparison of fl-OPN ELISA

	IBL	Assay Designs	R&D Quantikine	In house
Capture antibody	Anti-human OPN (O-17), rabbit polyclonal IgG, recognizes N-terminal ¹⁷IPVKQADSGSSEEKQ	Mouse monoclonal antibody to OPN, epitope includes ¹⁶²SVVYGLRSKSK	Mouse monoclonal antibody to OPN	Mouse monoclonal anti-human OPN to N-fragment
Antigen	Untagged rOPN/CHO cells	6x-C-terminal His tagged rOPN/mouse NS0 cells	6x-C-terminal His tagged rOPN/mouse NS0 cells	6x-C-terminal his tagged rOPN/E. coli
Detecting antibody	Anti-human OPN (10A16), mouse IgG, Fab'-HRP, recognizes to the right of thrombin cleavag site ¹⁷⁰KSKKFRRPDIQYPDATDE	Biotinylated monoclonal antibody to OPN. Epitope is located after the thrombin cleavage site,	Polyclonal anti-OPN conjugated to HRP	Mouse monoclonal anti-human OPN to C-fragment
Detection and system	Full-length OPN, HRP-TMB	Full-length OPN, biotin-streptavidin-AP	Full-length OPN, HRP-TMB	Full-length OPN, biotin-streptavidin-HRP
Measur range	5–320 ng/ml	2–32 ng/ml	0.31–20 ng/ml	0.078–10 ng/ml
Sensitivy	5–320 ng/ml	0.110 ng/ml	0.011 ng/ml	0.014 ng/ml

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