A sensitive homologous radioimmunoassay for human relaxin-2 (h-RLX-2) based on antibodies characterized by epitope mapping studies.
We present a sensitive homologous radioimmunoassay (RIA) for the quantitative determination of human relaxin (hRLX) in human serum, plasma, seminal plasma, and urine. This assay is based on a rabbit antiserum which was generated using recombinant hRLX-2 as immunogen. Using 125I-hRLX-2 as tracer and a total incubation time of 20 - 24 hours the radioimmunoassay showed linearity in a range of 60 - 4000 ng/l, a lower detection limit of 38 ng/l and a mean recovery rate of 98.5%. Intraassay variation was 4.0% (mean = 526 ng/l) and 11.9% (mean = 2368 ng/l), and interassay variation 10.7% (mean = 256 ng/l) and 13.1% (mean = 2368 ng/l). Using hRLX-2 hexapeptides on polystyrene pins, epitopes recognized by the hRLX-2 specific rabbit antiserum were determined experimentally, and compared to predicted epitopes. Both methods led to comparable results. The antiserum, recognizing different epitopes, showed no cross-reactivity with human insulin, hZn-insulin, hIGF-I, hIGF-II, human inhibin alpha-subunit, two different forms of seminal plasma inhibin like peptide, spermolaxin, ubiquitin, prolactin, LH, FSH and hCG.
Armbruster
F P
FP
Immundiagnostik AG, Wiesenstr. 4, D-64625 Bensheim, Germany. immundiagnostik@t-online.de
Grön
H J
HJ
Maier
I
I
Becker
S
S
Bailer
S M
SM
Lippert
T H
TH
Seeger
H
H
Klöppinger
M
M
Tampe
J
J
Stoeva
S
S
Voelter
W
W
D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology*; D018604:Epitope Mapping; D004958:Estradiol / Q000008:administration & dosage / Q000627:therapeutic use; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011247:Pregnancy; D011487:Protein Conformation; D011863:Radioimmunoassay / Q000379:methods*; D012065:Relaxin / Q000032:analysis* / Q000097:blood / Q000276:immunology / Q000652:urine; D012661:Semen / Q000737:chemistry; D012680:Sensitivity and Specificity
D000906:Antibodies; D004958:Estradiol; D012065:Relaxin