Different forms of insulin-like growth factor-binding protein-3 detected in serum and seminal plasma by immunofluorometric assay with monoclonal antibodies.
Monoclonal antibodies against recombinant insulin-like growth factor-binding protein-3 (IGFBP-3) were produced to study the various forms of IGFBP-3 and to develop a specific immunofluorometric assay. We tested seven antibodies that showed no cross-reactions with the other five human IGFBPs. By immunoblotting, the main bands in normal serum were seen at > 90, 45, 41, 29, and 25 kDa. In pregnancy serum, the 29-kDa was stronger, and the double band at 41-45 kDa was weaker or totally absent. We characterized two immunofluorometric assays. IGF-I had no effect on either assay. Added IGF-II lowered the amount of recombinant IGFBP-3 measured by the 5C11/7F8 assay, but not by the 1B6/5C11 assay. In normal serum and follicular fluid, IGFBP-3 measurements were lower by the 5C11/7F8 assay, but in most pregnancy sera and amniotic fluids the assays gave similar results. The 5C11/7F8 assay also detected IGFBP-3 in seminal plasma, whereas the 1B6/5C11 assay did not. We conclude that the results of IGFBP-3 measurement depend on the antibodies used, and that different antibodies are suitable for the IGFBP-3 measurement in different body fluids.
Koistinen
H
H
Department I of Obstetrics and Gynecology, Helsinki University Central Hospital, Finland.
Seppälä
M
M
Koistinen
R
R
D000653:Amniotic Fluid / Q000737:chemistry; D000818:Animals; D000911:Antibodies, Monoclonal; D002352:Carrier Proteins / Q000032:analysis* / Q000097:blood; D005260:Female; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D015151:Immunoblotting; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011247:Pregnancy; D011994:Recombinant Proteins / Q000032:analysis; D012661:Semen / Q000737:chemistry*
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II