Uses for Recombinant Protein Drugs - Biotechnology and Your Health: Pharmaceutical Applications - page 77

only in the laboratory. Regardless,TNF is one of the major players
in inflammation. Two other biologic drugs that target TNF are used
to treat RA. Both are monoclonal antibodies that bind to TNF itself
and take it out of action and eventually out of the body. Infliximab
(Remicade ® ) is a monoclonal antibody to TNF, engineered so that
only the TNF binding ends of the antibody contain the mouse
sequence; the rest of the antibody looks like a human antibody
protein. This reduces the chance that patients treated with inflix-
imab will develop an immune response to it. Infliximab is also
used to treat Crohn's disease , an inflammatory condition that
affects the intestines. Another TNF-targeting antibody used in
RA, adalimumab (Humira ® ), was designed so that it is essentially
entirely a human antibody.
Scientists have also developed the ability to engineer monoclonal
antibody molecules into plants. Although no plant-produced anti-
body has been tested in humans, a plant-produced human mono-
clonal antibody to the rabies virus was able to protect hamsters from
rabies after they were exposed to the virus. Development in this area has
been slowed by technical issues of efficiency, economics of production
of monoclonal antibodies in plants, as well as environmental and safety
concerns about growing genetically engineered antibody-producing
plants in open fields. Biotechnologists must first overcome the tech-
nical problems that to date have prevented plant production from
being economically competitive with production in cell culture.

Vaccines
Vaccines made with recombinant proteins marshal an immune
response to specific viruses to treat or prevent disease. Vaccines
to prevent infection with the liver-damaging hepatitis viruses
(Twinrix ® , Recombivax HB ® , and Engerix-B ® ) include a recombi-
nant version of a hepatitis virus B protein. Recombinant hepatitis
B protein is also included in some combination vaccines given to
children. Comvax ®

also includes a recombinant flu virus protein,