PURPOSE: To obtain an antibody having excellent specificity to materials to be examined, etc. by inducing immunity non-responsiveness by dosing of the covalent bonded material of the 2nd antigen and a D-glutamic acid-D-lysine copolymer to mammals then immunizing the same with the 1st antigen.

CONSTITUTION: The covalent bonded material of the 2nd antigen having ≥1 antigen determining groups similar to the 1st antigen in structure and a copolymer of D-glutamic acid and D-lysine (D-GL) is dosed to mammals to induce the immunity non-responsiveness to said 2nd antigen is said animals, after which said animals are immunized with said 1st antigen. Then said material has high specificity to the 1st antigen and a low cross characteristic with said 2nd antigen. The intended antibody is obtained. A copolymer of, for example, about 27000W 120000mol.wts. and about (70:30)W(30:70)molar ratios between the D- glutamic acid and the D-lysine is used for said D-GL.