For those who might wonder about how we get recombinant human milk proteins,
I thought this patent might be of interest--patent # 5942274. I wonder if
the woman who was 8 months pregnant and donated her cells for production of
these recombinants was duely compensated? Of course I wonder for what
reasons she was having such an invasive procedures done to breast tissue
during pregnancy. She might have needed some of that milk producing tissue
for her baby. How generous of her to supply the biotech industry with her
tissue so that we can mimic breast milk. I guess I'm being cynical, huh?
Valerie W. McClain, IBCLC
DETAILED DESCRIPTION OF THE INVENTION
Preparation of a cDNA Library
To produce human alpha-lactalbumin and beta-casein in microorganisms,
epithelial cells from the human mammary gland must be obtained which may be
treated with hormones, such as prolactin, to induce protein synthesis.
Appropriate cell lines are commercially available from a variety of sources,
such as the Michigan Cancer Foundation. From the prolactin treated cells,
mRNA may be obtained by isolating total RNA (J. M. Chirgwin, A. E. Przybyla,
R. J. MacDonald and W. J. Rutter, Biochemistry, 18, 5294-5299 (1979)), and
then the poly (A)+RNA fraction (H. Avis and P. Leder, Proc. Natl. Acad. Sci.,
69, 1408-1412 (1972)). Single and double stranded cDNA are prepared from this
(U. Gubler and B. J. Hoffman, Gene, 25, 263-269 (1983)), followed by ligation
and transfection to construct the library, ("Current Protocols in Molecular
Biology", F. M. Ausubel, R. Brent, R. E. Kingston, D. D. Moore, J. G.
Seidman, J. A. Smith and K. Struhl, editors, John Wiley and Sons, New York
(1987)) with subsequent isolation of the particular genes.
As an alternative procedure, a commercial cDNA library (HZ1037) is available
from Clontech Labs, Inc. (Palo Alto, Calif.), prepared from human mammary
tissue cells from a woman 8 months pregnant. Such a cDNA library has been
used (Menon and Ham, J. Cell Biol., 107, 523a (1989); S. Menon and R. G. Ham,
Nucl. Acids Res., 17, 2869 (1989)) to prepare, clone and sequence human
beta-casein cDNA.
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