Extract: During the past decade, important advances in biotechnology include the invention of an array of technologies that have resulted in the generation of monoclonal antibodies with human sequences. These technologies include humanization of mouse antibodies using molecular techniques, development of antibodies from human lymphocyte cDNA libraries by phage or ribosome displays, and the generation of fully human antibodies utilizing transgenic mice that carry the human immunoglobulin genes. These humanized or fully human antibodies are able to overcome the potential problem of eliciting immune responses by human hosts to mouse sequences present in murine antibodies. Monoclonal antibodies have emerged as important therapeutic reagents for the treatment of cancer, autoimmune disorders, and infectious diseases; and, to date, 17 therapeutic antibodies have been approved by the U.S. FDA and several hundred are in various stages of development.