Inappropriate expression of IL-6 plays a role in various inflammatory conditions, degenerative diseases, and cancers. Several model systems have been developed that can specifically block IL-6-receptor interactions. Here we present a simple and highly effective approach based on vaccination with a pool of specifically mutated IL-6 analogues to induce a neutralizing IL-6 antibody response in mice. Judged by the ability of the analogues to bind to heterologous anti-IL-6 antibodies and cellular IL-6 receptors the IL-6 analogues seemed to have a three-dimensional structure comparable to that of wild-type IL-6. Injection of them broke self-tolerance and induced an immune response to IL-6, presumably because of the amino acid differences between the analogues and wild-type IL-6. This resulted in a long-lasting anti-IL-6 antibody-mediated IL-6 deficiency that blocked experimentally induced IL-6-mediated pathology.