The invention provides a preparation method of an
antibody conjugate containing an sLeX
tetrasaccharide structure, which comprises the following steps: S1, sequentially adding Endo S2
enzyme and alpha-L-
fucosidase into a target
antibody, and respectively analyzing
glycosylation to avoid modification site conflict or
carbohydrate chain structure interference; s2, adding the accurately represented
antibody in the S1, B4GalT1 and UDP-Gal into a
Tris-HCl
system containing Mn < 2 + >, and incubating to obtain a reaction solution I; s3, the reaction liquid I, ST3Gal3, CMP-Neu5Ac and
Tris-HCl containing Mg < 2 + > are taken and mixed, and incubation is carried out; adding CMP-N-acyl
neuraminic acid phosphodiesterase for reaction, and purifying
Protein A to obtain a purified antibody I; s4, the purified antibody I, alpha1, 3 FucT-2HR, GDP-Fuc and
Tris-HCl containing Mg < 2 + > are taken and mixed, and incubation is performed; and purifying
Protein A to obtain a target product. According to the modified antibody obtained by the invention, while the targeting property is improved, the binding affinity of the antibody and a tumor
cell surface
antigen can be enhanced, so that the immune blocking activity of the antibody is further enhanced, and dual improvement of the targeting property and the activity is realized.