An Antibody That Detects Specific Sugar-Protein Combinations for Diagnostics

This patent describes a unique antibody designed to precisely recognize a specific sugar-protein structure, particularly a 'fucosylated glycopeptide' found on certain proteins like alpha-fetoprotein (AFP), which is useful for medical tests.

What it covers

This patent claims a special type of antibody, called a monoclonal antibody, that can find and stick to a very specific target. The target is a 'glycopeptide' (a protein with a sugar attached) that has a 'core fucose moiety' (a specific sugar part) and a particular sequence of amino acids near where the sugar is attached. Crucially, the antibody described in claim 1 and 11 is defined by its unique 'complementarity-determining regions' (CDRs) and reacts with a glycopeptide of formula (1) but not with similar glycopeptides of formulas (2), (3), or (4). For example, it reacts with fucosylated alpha-fetoprotein (AFP), even after the protein has been treated with chemicals like SDS and DTT, which can change its shape, as described in claims 4 and 5.

What it doesn't cover

• —Does not cover antibodies that react with glycopeptides of formula (2), (3), or (4) as defined by SEQ ID NOs: 14, 15, and 16 in the patent.
• —Does not cover antibodies that react with alpha-fetoprotein (AFP) that is not fucosylated, even if pretreated with SDS and DTT, as specified in claim 6.
• —Does not cover antibodies that do not have the specific amino acid sequences for the heavy and light chain CDRs as listed in SEQ ID NOs: 1-6 or 7-12.
• —Does not cover antibodies that recognize only the amino acid part of the glycopeptide without the core fucose moiety being part of the epitope.

The clever bit

The clever part is creating an antibody that is highly selective, recognizing not just a protein, but a specific combination of a sugar and protein structure (a glycopeptide) where both the sugar and specific amino acids form the binding site. This allows it to differentiate between very similar molecules, like fucosylated versus non-fucosylated AFP, which is critical for accurate diagnostic tools.

Why it matters

This patent is important for medical diagnostics, especially in detecting specific forms of proteins that can indicate diseases. Fucosylated alpha-fetoprotein (AFP) is a known biomarker, often elevated in certain cancers like liver cancer. An antibody that can precisely distinguish between fucosylated and non-fucosylated AFP, or different glycopeptide structures, allows for more accurate and specific diagnostic tests. This specificity helps doctors identify disease markers more reliably.

Real-world examples

• 1.Diagnostic kits for liver cancer screening
• 2.Laboratory tests for biomarker detection
• 3.Research tools for studying protein glycosylation
• 4.Immunoassays for fucosylated alpha-fetoprotein (AFP)