Evaluation of factors affecting the performance of enzymatic SPan-1 immunoassays for pancreatic cancer.
An avidin-biotin complex (ABC) sandwich enzymatic immunoassay was developed utilizing SPan-1, a murine monoclonal antibody of the IgM isotype. Biotin was attached to the epsilon-amino group of lysines of SPan-1 using biotin-N-hydroxysuccinimide esters with or without a spacer (aminohexane). Addition of biotin to carbohydrates was with biotin hydrazide after periodate oxidation of the immunoglobulin. The resultant assays were compared to a sandwich radioimmunoassay and to another form of the SPan-1 enzymatic immunoassay in which oxidized horseradish peroxidase had been directly conjugated to SPan-1. Comparable antigen detection limits were obtained regardless of whether biotin was added to the peptide or carbohydrates or whether a spacer was used or not. The ABC assay had approximately the same SPan-1 antigen detection limit as the radioimmunoassay. 90.6% of the human pancreatic cancer sera tested positive in the ABC assay as compared to a previously reported 93% positive rate with a radioimmunoassay.
Ho
J J
JJ
Gastrointestinal Research Laboratory, Veterans Administration Medical Center, San Francisco, CA 94121.
Chung
Y S
YS
Ryan
W
W
Henslee
J G
JG
Kim
Y S
YS
D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm / Q000276:immunology*; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000032:analysis*; D001710:Biotin; D004306:Dose-Response Relationship, Immunologic; D006735:Horseradish Peroxidase; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007124:Immunoenzyme Techniques; D007457:Iodine Radioisotopes; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000276:immunology
D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D015295:Antigens, Tumor-Associated, Carbohydrate; D007457:Iodine Radioisotopes; D001710:Biotin; D006735:Horseradish Peroxidase