Method for separating antibody, and method for testing on disease

A method for detecting the presence or absence of a disease(s), the risk of developing a disease(s), the degree of progression of a disease(s), and/or the degree of progression of aging,

• wherein the method comprises the following steps (a), (b), and (c):
• (a) adding a solution containing an antibody obtained from a subject to a column filled with an insoluble carrier on which an Fc-binding protein is immobilized, to allow an antibody(ies) to be adsorbed on the carrier;
• (b) eluting the antibody(ies) adsorbed on the carrier using an eluent, to obtain data of a separation pattern of an antibody(ies);
• and
• (c) detecting the presence or absence of a disease(s), the risk of developing a disease(s), the degree of progression of a disease(s), and/or the degree of progression of aging, in the subject, using said data as an indicator,
• wherein the data are a characteristic(s) of the separation pattern of the antibody(ies),
• wherein the Fc-binding protein is any one of the following polypeptides (1) to (4):
• (1) a polypeptide comprising the 17th to 192nd amino acid residues of the amino acid sequence of SEQ ID NO:
• 1, wherein, in the 17th to 192nd amino acid residues, at least the 176th valine is substituted with phenylalanine;
• (2) a polypeptide comprising the 17th to 192nd amino acid residues of the amino acid sequence of SEQ ID NO:
• 1, wherein, in the 17th to 192nd amino acid residues, at least the 27th valine is substituted with glutamic acid, the 29th phenylalanine is substituted with isoleucine, the 35th tyrosine is substituted with asparagine, the 48th glutamine is substituted with arginine, the 75th phenylalanine is substituted with leucine, the 92nd asparagine is substituted with serine, the 117th valine is substituted with glutamic acid, the 121st glutamic acid is substituted with glycine, the 171st phenylalanine is substituted with serine, and the 176th valine is substituted with phenylalanine;
• (3) a polypeptide comprising the 17th to 192nd amino acid residues of the amino acid sequence of SEQ ID NO:
• 1, wherein, in the 17th to 192nd amino acid residues, at least the 27th valine is substituted with glutamic acid, the 29th phenylalanine is substituted with isoleucine, the 35th tyrosine is substituted with asparagine, the 48th glutamine is substituted with arginine, the 75th phenylalanine is substituted with leucine, the 92nd asparagine is substituted with serine, the 117th valine is substituted with glutamic acid, the 121st glutamic acid is substituted with glycine, and the 171st phenylalanine is substituted with serine;
• and
• (4) a polypeptide comprising the amino acid sequence of any one of the polypeptides (1) to (3), wherein the amino acid sequence further comprises 1 to 10 amino acid mutations at a position(s) other than the above described substitution(s).