The invention belongs to the technical field of
biology, and discloses a nano
antibody targeting
B cell CD20 and application of the nano
antibody. The
amino acid sequences of the complementarity determining regions CDR1-CDR3 of the nano
antibody are selected from SEQ ID NO.1-9. The nano antibody provided by the invention can be specifically combined with B cells in
human blood, so that the B cells generating
pathological antibodies are removed. Compared with the traditional antibody, the nano antibody provided by the invention has the advantages of smaller molecular weight, high stability, low cost, easiness in expression and high expression quantity, and is suitable for large-scale production. The nano antibody is combined with the
solid-phase carrier, B cells in blood can be cleared in a targeted mode, the number of the B cells in the blood of a patient can be reduced in a short time, the
antibody level can be reduced, therefore, the
life quality is improved, complications are reduced, and a new treatment choice is provided for the patient who is ineffective or intolerant to traditional treatment.