Disclosed is an interleukin-23 p19 (IL-23p19) antibody or antigen binding fragment comprising: a) a light chain variable domain, or antigen binding fragment thereof, comprising CDRL1, CDRL2 and CDRL3, wherein: CDRL1 comprises the sequence of SEQ ID NO: 36 CDRL2 comprises the sequence of SEQ ID NO: 41 and CDRL3 comprises the sequence of SEQ ID NO: 46 and b) a heavy chain variable domain, or antigen binding fragment thereof, comprising CDRH1, CDRH2 and CDRH3, wherein: CDRH1 comprises the sequence of SEQ ID NO: 19 CDRH2 comprises the sequence of SEQ ID NO: 25 and CDRH3 comprises the sequence of SEQ ID NO: 31. Further disclosed is an isolated nucleic acid encoding said antibody or antigen binding fragment, and an expression vector and host cell comprising said nucleic acid. Also disclosed is a method for producing said antibody or antigen binding fragment, and a pharmaceutical composition comprising said antibody or antigen binding fragment. Also disclosed is the use of the antibody or antigen binding fragment in the manufacture of a medicament for the treatment of arthritis, psoriasis, inflammatory bowel disease, multiple sclerosis, systemic lupus erythematosus, diabetes, and cancer.
