Use of a single domain may provide certain benefits: (a) focusing of the immune response on the epitopes of lytic CD8+ and CD4+ T cells and reducing the immune response, which has no lytic potential and is not protective; (b) excluding autoepitopes as decoy epitopes with specific T cell immune response potentiating tumor growth; and (c) reducing size of DNA vaccine, which would result in a more efficacious DNA delivery [103,104]. The gene discussed is CD4; the disease is neoplasm.