1. A method for treating an autoimmune disease or an inflammatory disease, comprising administering to a mammal in need of treatment an isolated antibody or antigen-binding fragment thereof that specifically binds to human, murine and cynomolgus monkey CXCL13, wherein the antibody or antigen-binding fragment comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH comprises the three complementarity determining regions HCDR1, HCDR2, HCDR3 of SEQ ID NO: 4, SEQ ID NO. 5, and SEA ID NO:6, respectively, and wherein the VL comprises the LCDR1, LCDR2, and LCDR3 regions of SEQ ID NO: 9, SEQ ID NO: 10, and SEQ ID NO: 11, respectively, or the LCDR1, LCDR2, and LCDR3 regions of SEQ ID NO: 16, SEQ ID NO: 10, and SEQ ID NO: 11, respectively, wherein the autoimmune disease or inflammatory disease is multiple sclerosis (MS), Systemic Lupus Erythematosis (SLE) or arthritis or wherein the inflammatory disease is associated with a Helicobacter bacterial infection.