A 22 KDA HUMAN GROWTH-HORMONE SPECIFIC ENZYME-LINKED-IMMUNOSORBENT-ASSAY

A specific sandwich enzyme-linked immunosorbent assay (ELISA) was deve loped for human growth hormone (hGH) with molecular weight of 22 kDa ( 22 khGH). To prepare the 22k hGH specific antibody, a peptide (P-15) c orresponding to residues 32-46 in 22k hGH was synthesized and used to immunize rabbits, because a 20k hGH variant was known to lack this pep tide sequence. The assay method was developed using a combination of a n anti P-15 polyclonal antibody (YK-2) coated on the microtiter well a s a catching antibody and another polyclonal antibody against 22k hGH as a peroxidase-conjugated detecting antibody. The assay sensitivity w as 1 ng/ml for 22k hGH, and cross-reactivity with other pituitary prot ein hormones as well as the 20k hGH variant was less than 0.01%, respe ctively. Furthermore, the 22k hGH content was measured precisely even in the presence of 20k hGH in this ELISA system.