A human antibody kappa-type light chain complex-containing composition of the present invention comprises a complex which is formed by binding human antibody kappa-type light chain and at least one metal ion selected from the group consisting of a group 10 element, a group 11 element and a group 12 element, wherein the human antibody kappa-type light chain is a dimer, two C-terminal cysteines of the human antibody kappa-type light chains binds together by an interaction with the metal ion, and 0.1 mol or more of the metal ion binds to 1 mol of human antibody kappa-type light chain.本發明之含有人類抗體κ型輕鏈複合體之組成物包含結合了人類抗體κ型輕鏈與金屬離子的複合體,該金屬離子係選自於由第10族元素、第11族元素及第12族元素所構成群組中之1種以上;前述人類抗體κ型輕鏈為二聚物;且,2個前述人類抗體κ型輕鏈之C末端的半胱胺酸係透過前述金屬離子而結合,並且,每1莫耳之前述人類抗體κ型輕鏈結合有0.1莫耳以上之前述金屬離子。
