Novel antagonists of MCP proteins, in particular of MCP-1 protein, can be obtained by generating MCP mutants whose GAG binding site, located at the N-terminal of MCP proteins, is eliminated following non-conservative substitutions. Compounds prepared in accordance with the present invention can be used in the treatment or prevention of diseases related to an undesirable activity of MCP proteins such, such as inflammatory disease, autoimmune diseases, vascular diseases, and cancer.