Solid-phase double-antibody radioimmunoassay of pepsinogen I in serum.
A solid-phase radioimmunoassay for the determination of pepsinogen I in serum has been developed. The antibody was raised in rabbits with pepsinogen I isolated from urine as previously described. Radioiodination was carried out with a chloramine-T procedure resulting in a tracer with excellent shelf life. In the standard procedure with a 24-h incubation time, followed by 2-h incubation with a second antibody coupled to a solid phase, 50 microliter serum was analyzed, standard range 1.88-60 ng PG I. An eight times more sensitive method was also developed using sequential saturation techniques. Specificity studies demonstrated 0.6% crossreactivity with PG II. The immunoreactivity of PG I purified from urine was nearly identical with the immunoreactivity of PG I purified from gastric mucosa. The levels of PG I in serum from 121 control subjects were similar to those obtained with conventional phase separation methods. It is concluded that the method is simple, precise and free from non-specific serum interference.
D000818:Animals; D000918:Antibody Specificity; D004355:Drug Stability; D005260:Female; D005753:Gastric Mucosa / Q000032:analysis; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D010435:Pepsinogens / Q000032:analysis / Q000097:blood* / Q000276:immunology; D011817:Rabbits / Q000276:immunology; D011863:Radioimmunoassay / Q000379:methods*; D012016:Reference Values
D007457:Iodine Radioisotopes; D010435:Pepsinogens