70 • Impacts of Applied Genetics— Micro-Organisms, Plants, and Animals 
More hypothetically, molecular cloning may 
lead to three other uses of antigens as well: vac- 
cination against parasites, such as malaria and 
hookworm (see Tech. Note 7, p. 80.); immuniza- 
tion in connection with cancer treatment; and 
counteracting abnormal antibodies, which are 
made against normal tissues in the so-called 
"autoimmune diseases,” such as multiple sclero- 
sis. (See Tech. Note 8, p. 81.) 
INTERFERONS 
Interferons are glycoproteins normally made 
by a variety of cells in response to viral infec- 
tion. All interferons (see Tech. Note 9, p. 81) can 
induce an antiviral state in susceptible cells. In 
addition, interferon has been found to have at 
least 15 other biochemical effects, most of 
which involve other elements of the immune 
system. 
Promising preliminary studies have sup- 
ported the use of interferon in the treatment of 
such viral diseases as rabies, hepatitis, varicella- 
zoster (shingles), and various herpes infections. 
To date, the effect of interferon has been far 
more impressive as a prophylactic than as a 
therapeutic agent. The interferon produced by 
Genentech, for example, has been shown to pro- 
tect squirrel monkeys from infection by the le- 
thal myocarditis virus. Once interferon is avail- 
able in quantity, large-scale tests on human pop- 
ulations can be conducted to confirm its ef- 
ficacy in man. 
Several production techniques are being ex- 
plored. (See Tech. Note 10, p. 81.) Extraction of 
interferon from leukocytes (white blood cells), 
the current method of choice, may have to com- 
pete with tissue culture production as well as 
rDNA. (See table 5.) 
Recombinant DNA is widely regarded as the 
key to mass production of interferons, and 
important initial successes ha\e already been 
achieved. Each of the four major biotechnology 
companies is working on improved production 
methods, and all have reported some success. 
An enormous amount remains to he learned 
about the interferon system. It now appears 
that the interferons are simply one of many 
families of molecules involved in |)hvsiological 
regulation of response to disease. Only now 
have molecular biology and genetics made their 
study— and perhaps their use— possible. 
Table 5.— Summary of Potential Methods for Interferon Production 
Means of production 
Types of 
interferon 
produced 
Potential 
for 
scale-up 
Present projected 
($/10® units) 
Problems 
Potential for 
improvement 
“Buffy coat” leukocytes 
leukocyte, 95% 
fibroblast, 5% 
No 
50 — 
— lack of scale-up 
—pathogen contamination 
—minimal 
Lymphoblastoid cells 
leukocyte, 80% 
fibroblast, 20% 
Yes 
— =25 
— poor yields 
—cells derived from tumor 
— improved yields 
—expression of 
fibroblast 
interferon 
Fibroblasts 
fibroblast 
Yes 
43-200 =1-10 
—cell culture 
—economic competition 
with recombinant DNA 
— improved yields 
— improved cell- 
culture 
technology 
—expression of 
leukocyte-type 
interferon 
Recombinant DNA 
leukocyte or 
fibroblast 
Yes 
— =1-10 
—does not produce 
interferon 
— improved yields 
— in vitro drug stability 
— pooryieids —modified 
interferons 
—drug approval 
—possible economic 
competition with fibroblast 
cell production 
SOURCE: Office of Technology Assessment. 
