Understanding The Immune System

Another facet of recombinant DNA technology involves gene therapy It may someday be possible to remove disease-causing defective genes, or to replace them with normal genes. A prime candidate for gene therapy is severe combined immunodeficiency disease, or SCID (see Immunodeficiency Diseases), which is caused by lack of an enzyme due to a single missing gene. The plan is to introduce the missing gene into a harmless virus, then mix the recombinant virus with stem cells from the patient's bone marrow. When the virus splices its genes into those of the bone marrow cells, it simultaneously introduces the gene for the missing enzyme. After the treated marrow cells begin to produce the missing enzyme, the marrow can be injected back into the patient.

Immunogegulation

Research into the delicate and complex checks and balances that regulate the immune response is leading not only to an appreciation of the events involved in normal immunity, but also to abnormalities of immune functions. Eventually it may be possible to treat diseases such as systemic lupus erythematosus by selectively suppressing parts of the immune system that are overactive and selectively stimulating those that are underactive.       The SCID-hu Mouse The SCID mouse, which lacks a functioning immune system of its own, is helpless to fight infection or reject transplanted tissue. By transplanting immature human immune tissues and/or immune cells into these mice, scientists have created an in vivo model that promises to be of immense value in advancing our understanding of the immune system.