Advances in Immunology
One of the more remarkable technologies that is evolving is ge-netic engineering, which involves the use of recombinant DNAtechnology. Two facets exist with this technology. The first per-mits scientists to combine genes from one type of organism with genes of a second organism. This type of technology allows cells and microorganisms to manufacture proteins, monokines and lymphokines, which can alter and enhance immune system func-tion. The second facet of recombinant DNA technology involves gene therapy. For example, if a particular gene is abnormal or missing, a recombinant gene can be inserted onto a virus particle. When the virus splices its genes, it will automatically insert the missing gene, which theoretically will correct the situation and revitalize the immune system in an immune deficiency disorder. These genes can be carried via harmless viruses, inactivated retro-viruses, grafted onto a protein carrier, or hidden in fat globules that are known as liposomes (Delves & Roitt, 2000b). Extensive research into recombinant DNA technology and gene therapy is ongoing.
Stem cell research also is underway. The stem cell is known as a precursor cell that continually replenishes the body’s entire supply of both red and white cells. Stem cells represent only a small portion of all types of bone marrow cells. Research con-ducted with mouse models has demonstrated that once the im-mune system has been destroyed experimentally, it can be completely restored with the implantation of just a few purified stem cells. Stem cell transplantation has been carried out in hu-mans with certain types of immune dysfunction, such as severe combined immunodeficiency (SCID) (Parslow, Stites, Terr & Imboden, 2001). Clinical trials using stem cells are underway in patients with a variety of disorders with an autoimmune component, including systemic lupus erythematosus, rheuma-toid arthritis, scleroderma, and multiple sclerosis (Davidson & Diamond, 2001).
A successful immune response eliminates the inciting antigen. Once the antigen that has stimulated the immune response is eliminated, the response returns to a nearly normal level. This process, known as immunoregulation, balances and counter-balances the immune response. For example, autoimmune dis-eases can be better controlled by suppressing areas of the immune system that are overactive and boosting those areas that are under-active. Immunoregulation research holds the promise of prevent-ing graft rejection and aiding the body in dispersing cells that are cancerous or infected (Delves & Roitt, 2000b).