Abstract: An immunoassay of proteolytic protein fragments is described, including immunoassays of proteolytic fragments of Insulin-like Growth Factor Binding Proteins (IGFBPs). In one embodiment, a sandwich-type “two-site” immunoassay involves two different recognition antibody partners, in which one antibody is specific for a proteolytic epitope of a protein fragment, and the other is specific for the protein fragment. An assay embodiment involves a first-step capturing of the protein fragment with a specific anti-protein antibody that binds to the proteolytic epitope of the protein fragment, and a second-step detection of the bound protein fragment with an antibody directed against the protein fragment. The various embodiments of the systems and methods of the invention are exemplified by immunoassays for proteolytic fragments of Insulin-like growth factor binding proteins (IGFBPs), such as IGFBP-1, IGFBP-3, and IGFBP-5.

Abstract: An immunoassay of phosphorylated isoforms (phosphoforms, phosphoisoforms) of peptides, proteins, or their various related forms is described. In one embodiment, a sandwich-type “two-site” immunoassays involving two different recognition antibody partners, in which one antibody is specific for the protein or peptide and the other is specific for a known or discovered phosphorylated amino acid residue. An assay embodiment involves a first-step capturing of the protein or peptide with a specific anti-protein antibody, and a second-step detection of the bound phosphorylated isoform of the protein with an antibody directed against a known phosphorylated residue coupled to a label or a reporter molecule. The various embodiments of the compositions and methods of the invention are exemplified by immunoassays for phosphoforms of IGFBPs, such as IGFBP-1 and IGFBP-5, which contain phosphorylated serine residues.

Abstract: The present invention discloses compositions and methods to measure an amount of Anti-Mullerian Hormone (AMH) in a sample, including a mammalian sample such as a primate, rodent, equine, or bovine sample. The compositions and methods herein also provide antibodies that bind to epitopes on AMH that are stable to proteolysis of AMH.