Subject: DNX Develops Three Pigs That Carry Human Hemoglobin in Their Blood 
Date: Published: 6/17/91 (91 lines)
Source: Wall Street Journal. Copyright Dow Jones & Co. Inc.

    Technology & Medicine:
    DNX Develops Three Pigs That Carry
    Human Hemoglobin in Their Blood
    ----
    By Jerry E. Bishop
    Staff Reporter of The Wall Street Journal

    PRINCETON, N. J. -- A small biotechnology company here, DNX
 Corp., jumped into the race to develop a genetically
 engineered hemoglobin that would be the basis of a synthetic
 blood.
    The closely held company announced it had succeeded in
 splicing the human hemoglobin gene into pigs.  Currently, DNX
 has three pigs with human hemoglobin circulating in their
 blood streams, John Logan, vice president for research, said
 in an interview.  Mr. Logan presented technical details of the
 experiments last night to the World Congress on Cell and
 Tissue Culture meeting in Anaheim, Calif.
    Hemoglobin is the iron-containing protein in red blood
 cells that carries oxygen from the lungs to tissues
 throughout the body and removes the carbon dioxide.  A number
 of efforts are under way to develop genetically engineered
 hemoglobin that could be mass-produced as a cheap synthetic
 blood.  Such a synthetic blood would be free of viruses such
 as the AIDS and hepatitis viruses that contaminate donated
 human blood.  It also could be given to any person without
 worries about bloodtype matching and it would have a longer
 shelf life than whole human blood.
    Such a synthetic blood would be useful for the military,
 particularly on the battlefield, and as transfusions for
 accident victims in remote locations.  It also could provide a
 backup supply when donated human blood is scarce.
    One such synthetic blood, however, has hit a stumbling
 block.  A spokesman for Upjohn Co. in Kalamazoo, Mich.,
 confirmed that the big drug maker had suspended human trials
 of a hemoglobin blood substitute using hemoglobin from
 cattle.  The bovine-derived hemoglobin was developed by
 Biopure Corp., a Boston-based biotechnology company.
    "There were some medical events that we didn't expect" in
 the volunteers who were receiving the synthetic blood made
 with the bovine hemoglobin, an Upjohn spokesman, James
 VanSweden, said.  "But we haven't given up on it," he added,
 noting that new animal experiments are underway.  Somatogen
 Inc. in Boulder, Colo., is developing a synthetic blood using
 human hemoglobin produced by genetically engineered bacteria.
 An attempt to genetically engineer tobacco plants to produce
 human hemoglobin is being made by Biosource Genetics Corp. in
 Vacaville, Calif.  Other companies in the field include Quest
 Biotechnology Inc. in Detroit, which has licensed its
 hemoglobin technology to four companies:  Baxter Healthcare
 Corp., Hemosol Inc. in Canada, Northfield Laboratories Inc. 
 in Chicago and Biopure.
    DNX said it believes genetically altered pigs will be able
 to produce hemoglobin in large volumes and at lower cost than
 would be possible with bacteria, yeasts or other cells
 commonly used in genetic engineering.  The company predicted
 that with pigs it could produce human hemoglobin at a cost of
 less than $1 a gram, a small fraction of the cost of most
 genetically engineered pharmaceuticals.
    DNX said it has been working with Pig Improvement Co. in
 Franklin, Ky., for several years on inserting "foreign" genes
 into pigs.  While splicing new genes into laboratory mice is
 becoming almost routine, inserting new genes into large
 animals has proven difficult.  The new gene is inserted into a
 test tube embryo while it is still a single cell.  The embryo
 is then implanted into a sow which gives birth to the
 genetically altered piglet.
    DNX has developed a "micro-injection" technique for
 inserting genes into embryos at the single cell stage.  Mr. 
 Logan said DNX and the researchers in Kentucky attempted to
 insert the human hemoglobin gene into more than 90 pigs
 before three were born with the human gene functioning and
 producing human hemoglobin.
    A second advance claimed by DNX researchers was the
 ability to separate the human hemoglobin from the porcine
 version in the pigs' blood.  The two hemoglobins are 85%
 identical molecularly and function in almost identical ways.
 Mr. Logan said the company had adapted a technology known as
 anion exchange chromotography for extracting and purifying
 the human hemoglobin.
    The company said it hopes to ask the U. S. Food and Drug
 Administration next year for permission to test its
 pig-produced human hemoglobin in human volunteers.

[This article is made available here by Dow Jones Co. for the
 personal and non-commercial use of callers to this bbs, in the
 hope that it will be of some help to those who are suffering
 from the disease and others who are seeking to help them.]