MONOCLONAL ANTIBODY SPECIFICALLY BINDING TO SUGAR CHAIN IN WHICH A TERMINAL SIALIC ACID RESIDUE IS BOUND TO GALACTOSE WITH ALPHA 2,6 LINKAGE, AND METHOD FOR MEASURING SUGAR CHAIN IN WHICH TERMINAL SIALIC ACID RESIDUE IS BOUND TO GALACTOSE WITH ALPHA 2,6 LINKAGE

20240151724

18/281484

March 18, 2021

A monoclonal antibody or an antibody fragment thereof is provided which specifically binds to a sugar chain in which a terminal sialic acid residue is bound to galactose with α2,6 linkage, and which does not bind to a sugar chain to which galactose having no sialic acid bound to a terminal is bound.

1. A monoclonal antibody or an antibody fragment thereof which specifically binds to a sugar chain in which a terminal sialic acid residue is bound to galactose with α2,6 linkage, and which does not bind to a sugar chain to which galactose having no sialic acid bound to a terminal is bound.

2. The monoclonal antibody or the antibody fragment thereof of claim 1, wherein a dissociation constant with respect to the sugar chain in which the terminal sialic acid residue is bound to galactose with α2,6 linkage is 1.0×10−8 or less.

3. The monoclonal antibody or the antibody fragment thereof of claim 1, wherein the bindability to the sugar chain in which the terminal sialic acid residue is bound to galactose with α2,6 linkage is 20 times or more with respect to the bindability to a sugar chain in which a terminal sialic acid residue is bound to galactose with α2,3 linkage.

4. The monoclonal antibody or the antibody fragment thereof of claim 1, wherein an amino acid sequence of a complementarity determining region (CDR) 1 of a heavy chain variable region (VH) of the antibody or the antibody fragment thereof comprises an amino acid sequence set forth in SEQ ID NO:1, an amino acid sequence of CDR2 of the VH comprises an amino acid sequence set forth in SEQ ID NO:2, an amino acid sequence of CDR3 of VH comprises an amino acid sequence set forth in SEQ ID NO:3, an amino acid sequence of CDR1 of a light chain variable region (VL) comprises an amino acid sequence set forth in SEQ ID NO:4, an amino acid sequence of CDR2 of VL comprises an amino acid sequence set forth in SEQ ID NO:5, and an amino acid sequence of CDR3 of VL comprises an amino acid sequence set forth in SEQ ID NO:6.

5. The monoclonal antibody or the antibody fragment thereof of claim 4, wherein an amino acid sequence of the VH of the antibody or the antibody fragment thereof comprises an amino acid sequence set forth in SEQ ID NO:13, and an amino acid sequence of VL comprises an amino acid sequence set forth in SEQ ID NO:14.

6. The monoclonal antibody or the antibody fragment thereof of claim 1, wherein an amino acid sequence of CDR1 of the VH of the antibody or the antibody fragment thereof comprises an amino acid sequence set forth in SEQ ID NO:7, an amino acid sequence of CDR2 of the VH comprises an amino acid sequence set forth in SEQ ID NO:8, the amino acid sequence of CDR3 of VH comprises an amino acid sequence set forth in SEQ ID NO:9, an amino acid sequence of CDR1 of VL comprises an amino acid sequence set forth in SEQ ID NO:10, an amino acid sequence of CDR2 of VL comprises an amino acid sequence set forth in SEQ ID NO:11, and the amino acid sequence of CDR3 of VL comprises an amino acid sequence set forth in SEQ ID NO:12.

7. The monoclonal antibody or the antibody fragment thereof of claim 6, wherein an amino acid sequence of the VH of the antibody or the antibody fragment thereof comprises an amino acid sequence set forth in SEQ ID NO:15, and an amino acid sequence of VL comprises an amino acid sequence set forth in SEQ ID NO:16.

8. A method for measuring a sugar chain in which a terminal sialic acid residue is bound to galactose with α2,6 linkage, the method comprising using the monoclonal antibody or the antibody fragment thereof of claim 1.

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