Chandra nodded and advanced the slide. “Assuming for the spread of the mutation through marriage and genetic dispersion, we would still be talking about a relatively small set of survivors from the initial breeding couplethree hundred to two thousand people, worldwide.” Chandra looked at Kate. “And these people would need a relatively constant supply of whole blood for transfusions to survive into adulthood, assuming the disease continues beyond infancy, and we have no reason to believe otherwise.”
It was one of the CDC bigwigs, a doctor/administrator named Deborah Rawlings, who said, “But there were no transfusions in the fifteenth century . . . or anywhere until the last century . . . .” She paused.
Kate stood in the light from the projector. “Precisely. For this trait to be passed down at all, the survivors would have had to have actually ingested blood. Literally fed blood to their children, if the children possessed the Jvirus recessiverecessive. Only in the last century would transfusions have saved the Jvirus mutation individuals.” She waited a minute for the full impact to settle on the specialists and administrators.
“Vampires,” said Ken Mauberly. “The myth has its origins in reality.”
Kate nodded. “Not fanged creatures of the night,” she said, “but members of a family who did have to ingest human blood in order to survive their own faulty immune systems. The tendency would be for secrecy, solidarity, inbreeding . . . the recessiverecessive traits would have been more frequent as a result, much as with the hemophilia which plagued the royal houses of Europe.”
An assistant virology researcher named Charlie Tate hesitantly raised his hand as if he were a high school student.
Kate paused. “Charlie?”
The young man adjusted his round glasses. “How in the hell . . . I mean, how did that first Jvirus sufferer find out that blood would save him . . . or her . . . I mean, how did someone start drinking blood?”
“In the Middle Ages,” said Kate, “there are records of noblewomen who bathed in blood because legend had it this would make their skin more beautiful. The Masai still drink lion's blood to absorb the animal's courage. Blood hasuntil recent decadesbeen the source of superstition and awe. “ She paused a second, looking at Chandra. “Now, with AIDS, it's regaining that terror and mystery.” Kate sighed and rubbed her cheek. “We don't know how it began, Charlie,” she said softly. “But once it worked, .the Jvirus sufferers had no choice . . . find human blood or perish.”
The silence stretched on for another thirty seconds before Kate went on. “Part of my work has been to end that cycle,” she said. “And it looks as if I have a solution.” She advanced the slide, and an image of a pig's face filled the screen.
The doctors in the room giggled despite themselves.
Kate smiled. “Most of you know about the DNX breakthrough on human blood substitute this past June“
Ken Mauberly held up his fountain pen. “Refresh our overworked administrative memories, please, Kate.”
“DNX is a small biotech lab in Princeton, New Jersey,” said Kate. “In June of this year they announced that they had perfected a way of producing human hemoglobin in pigs via genetic engineering. They've given the research to the FDA and are applying for human trials even as we speak.”
Mauberly tapped his pen against his lower lip. “How does this artificial hemoglobin help in the Jvirus research?”
“It's not really artificial hemoglobin,” answered Kate, “merely not created in the human body.” She advanced the slide carousel again. “Here you see a simplified schematic of the process. By the way, I've been working with an old friend, Doctor Leonard Sutterman, who is chief hematology consultant for DNX, as well as with Doctor Robert Winslow, chief of the Army's blood research division at the Letterman Institute of Research in San Francisco, so we're duplicating research with permission here and being careful not to tread on DNX's pending patents.
“Anyway, here is the schematic. First, the researchers extract the two human genes we know are responsible for producing hemoglobin in the human body.” Kate glanced at the administrators. “Hemoglobin, of course, is the oxygen-carrying component in the blood.
“All right, having extracted the genetic information, these genes are then copied and injected into dayold pig embryos taken from a donor pig. These embryos are then inserted into the womb of a second pig, where they grow to term and are born as normal, healthy piglets. The only difference is that these pigs have human DNA in them, directing them to produce human hemoglobin along with their own pig-variety blood.”
“Excuse me, Kate,” interrupted Bob Underhill. “What's the percentage on that?”
Kate started to answer and then paused. “On which, Bob? The number of successful transgenic pigs or on the amount of human hemoglobin the successful ones produce?”
Underhill spread his hands. “Either. Both.”
“About five pigs in a thousand successfully carry the transfers,” said Kate. “Of those, each averages about fifteen percent of their blood cells carrying humantype hemoglobin. But DNX is working on getting the ratio up closer to fifty percent of the cells.”
She waited a second, but there were no more immediate questions. Kate advanced the slide again. “You see here that DNX's real breakthrough is not in the genetic engineering . . . that was straightforward enough . . . but in patenting a process to purify the swine blood so that useful human hemoglobin can be recovered. This is what so excites my friends Doctor Leonard Sutterman and Doctor Gerry Sandier with the blood division of the Red Cross.”
Kate advanced the slide to an empty frame and stood a minute in the brilliant light. “Think of it, substitute human blood . . . only much more useful than whole blood or plasma.”
“How so?” asked Deborah Rawlings.
“Whole red blood cells are made of perishable membranes,” said Kate. “Outside the body they have to be refrigerated, and even then spoil after a month or so. Also, each cell carries the body's immune codes, so blood has to be matched by type if it's not to be rejected. Pure hemoglobin avoids both these problems. As a chemical, it can be stored for months . . . recent experiments show that it can even be freezedried and stored indefinitely. The Army's Doctor Winslow estimates that about ten thousand of Vietnam's fifty thousand battlefield fatalities could have been saved if this oxygenated blood substitute had been available. “
“But plasma already has the shelflife attributes you're talking about,” said Rawlings, “and it doesn't require expensive genetic engineering.”
“Right,” said Kate, “but it does require human donors. Plasma availability is restricted by the same factors that mean that whole blood is sometimes unavailable. The human hemoglobin acquired via the DNX process only requires pigs.”
“A lot of pigs,” said Alan Stevens.
“DNX figures that four million donor pigs could provide riskfree blood for the entire U.S. population,” Kate said softly. “And it would only take about two years to grow those donor pigs.”
Bob Underhill whistled again.
Mauberly raised his fountain pen like a baton. “Kate, I see where you're going with this for the RSProject. Someone with the Jvirus immunodeficiency disease could theoretically be injected with this genetically altered swine blood, but it seems to me that this wouldn't help at all.”
Kate nodded. “Right, Ken. The only genes cloned in the DNX process are those which govern the production of hemoglobin. This is my suggestion.” She clicked her last slide on and gave everyone a minute to study it.
“You see,” she said at last, aware that her voice was thickening with emotion for some reason, “what I've done is piggyback on Richard Mulligan, Tom Maniatis, and Frank Grosveld's work on transplanting human betaglobin genes via retrovirus for immunoreconstruction. Mulligan and the others have been concentrating on curing betathalassemics and adenosine deaminase deficiency, although they've also done some startling work with boosting tumorinfiltrating lymphocytes, TIL cells, with interleukin2 hormone, putting the cells back in cancer patients, and watching the geneboosted cells attack tumors.”