Immunomodulatory vaccines against autoimmune diseases

Abstract

Vaccines are for healthy people, to prevent them from becoming ill. Such prophylactic vaccines have been a great success. Therapeutic vaccines become more and more important, especially as life expectancy increases. Efforts to develop vaccines against such diseases as cancer, AIDS, hepatitis, tuberculosis, Alzheimer disease, and mad cow disease have not yet reached the stage where they can be successfully used on a daily basis. However, significant progress has been made in the realm of autoimmune diseases, resulting (at least in one case) in an immunomodulatory vaccine against multiple sclerosis that was developed in the author's laboratory, and that is in daily use by about 100,000 patients. The drug or therapeutic vaccine against the exacerbating-remitting type of multiple sclerosis is a copolymer of four amino acid residues, denoted Copaxone, which are related to myelin basic protein. This paper discusses Copaxone as well as a candidate immunomodulatory vaccine against myasthenia gravis, a peptide derived from the nicotinic acetylcholine receptor. Copolymer 1 (Cop 1, glatiramer acetate, Copaxone) is a synthetic amino acid random copolymer that is immunologically cross-reactive with myelin basic protein and suppresses experimental allergic encephalomyelitis in several animal species. Cop 1 slows the progression of disability and reduces the relapse rate in exacerbating-remitting multiple sclerosis patients. Cop 1 is a potent inducer of T helper 2 (Th2) regulatory cells in mice and humans; and Th2 cells are found in both the brains and spinal cords of Cop 1-treated mice and humans. MG and experimental autoimmune MG are T cell-regulated, antibody-mediated autoimmune diseases. Two peptides, representing sequences of the human AChR-alpha-subunit, p195-212 and p259-271, are immunodominant T-cell epitopes in MG patients and two strains of mice. Altered peptide ligand, composed of the randomly arranged two single amino acid analogs inhibits in vitro and in vivo MG-associated autoimmune responses. The active suppression is mediated by the CD4+ CD25+ immunoregulatory cells and is associated with the downregulation of Th1-type cytokines and upregulation of the secretion of IL-10 and the immunosuppressive cytokine transforming growth factor beta.