Novel immune modulating processes are provided in which the immunological state of a subject including mature subjects, mammals and humans, are down regulated in a selective manner, and as a subset in a dominant manner. The novel immunological state termed SIDR for selective immune down regulation is usefully applied to the immunological modulation or regulation of gene delivery components, artificially expressed genes, gene delivery systems and expression products of artificially introduced genes by such delivery systems, and infectious agents. SIDR is also useful when combined with other immune modulating treatments such as general immune suppression and anti-apoptosis. SIDR may also be used to selectively down regulate the immune response system of a subject to a wide variety of noncellular immunogenic components and to native antigens. Other processes for producing immune suppression by administering macromolecules or compounds to a subject so as to obtain or effect SIDR are also provided. Kits for carrying out the novel processes are also provided.