PROMED: Xenografts & primate viruses

woodall at wadsworth.org woodall at wadsworth.org
Tue Feb 28 12:39:09 EST 1995


XENOGRAFTS & PRIMATE VIRUSES
============================
 
Source: VOA Gopher - VOA broadcast, 27 Feb.1995 

SCIENCE TODAY: AIDS / BABOON THERAPY By DAVID MCALARY/WASHINGTON

INTRO:  U-S RESEARCHERS HAVE ENLISTED BABOONS IN THE FIGHT 
AGAINST AIDS.  THEY ARE HOPING TO TRANSFER THE IMMUNITY BABOONS 
ENJOY FROM THE H-I-V VIRUS THAT CAUSES AIDS TO PATIENTS IN THE 
ADVANCED STAGES OF THE DISEASE.  V-O-A SCIENCE CORRESPONDENT 
DAVID MCALARY REPORTS THAT THE RESEARCHERS CONSIDER THE 
FORTHCOMING EXPERIMENT A MEDICAL GAMBLE.

TEXT:  WITHIN A COUPLE OF MONTHS, DOCTORS FROM THE UNIVERSITIES 
OF PITTSBURGH AND SAN FRANCISCO WILL SURGICALLY TRANSPLANT BABOON
BONE MARROW CELLS INTO FIVE VOLUNTEERS FROM THE AIDS WARD OF SAN 
FRANCISCO GENERAL HOSPITAL.

BONE MARROW PRODUCES PRECURSOR CELLS CALLED STEM CELLS THAT 
MATURE INTO ALL TYPES OF BLOOD CELLS, INCLUDING THE WHITE ONES OF
THE IMMUNE SYSTEM.  H-I-V DESTROYS THE HUMAN IMMUNE SYSTEM, BUT  
NOT THAT OF BABOONS.  SO THE DOCTORS HOPE THAT INTRODUCING THE 
BABOON STEM CELLS INTO AIDS PATIENTS WILL HELP THEM MANUFACTURE 
ENOUGH RESISTANT IMMUNE CELLS TO FIGHT THE VIRUS.

                     // ILDSTAD ACTUALITY //

         THAT'S THE MOST HERETICAL OF ALL OUR POTENTIAL TRIALS.  
         EVERYTHING ELSE IS INVOLVING HUMAN TO HUMAN 
         TRANSPLANTATION.

                       // END ACTUALITY //

THIS IS TRANSPLANT SURGEON SUZANNE ILDSTAD OF THE UNIVERSITY OF 
PITTSBURGH, A CENTER OF PIONEERING RESEARCH INTO TRANSPLANT 
PROCEDURES.

                     // ILDSTAD ACTUALITY //

         NO ONE HAS EVER REPORTED ENGRAFTMENT OF HIGHLY PURIFIED 
         STEM CELLS -- WHICH ARE A WONDERFUL TECHNOLOGY -- IN 
         GENETICALLY DIFFERENT RECIPIENTS.  IT'S VERY EASY TO GET
         PURIFIED STEM CELLS TO TAKE IN GENETICALLY IDENTICAL 
         RECIPIENTS.  HOWEVER, WHEN ONE CROSSES GENETIC BARRIERS,
         THEN APPARENTLY DIFFERENT CONDITIONS ARE REQUIRED.

                       // END ACTUALITY //

STEM CELL TRANSPLANTS FREQUENTLY FAIL BECAUSE KILLER IMMUNE CELLS
COMBINED WITH THEM ATTACK THE RECIPIENT'S TISSUE, TREATING IT AS 
FOREIGN, JUST AS IT WOULD TREAT AN INFECTIOUS ORGANISM.  YET, 
RESEARCHERS HAVE LONG KNOWN THAT FILTERING THE KILLER CELLS OUT 
OF BONE MARROW STILL DOES  NOT  IMPROVE TRANSPLANT CHANCES.  IN 
1993, DR. ILDSTAD LEARNED WHY.

SHE FOUND THAT BONE MARROW CONTAINS ANOTHER CLASS OF CELLS WHICH 
HAS AN OPPOSITE PURPOSE FROM KILLER CELLS:  THEY HELP DONOR 
TISSUE ENGRAFT IN GENETICALLY DIFFERENT RECIPIENTS.  SHE CALLS 
THEM FACILITATING CELLS.  BECAUSE THEY RESEMBLE KILLER CELLS, THE
PROCEDURE TO REMOVE KILLER CELLS ALSO ELIMINATED THE FACILITATING
CELLS, DOOMING TRANSPLANT SUCCESS.

DR. ILDSTAD HAS BEEN ABLE TO SEPARATE THE FACILITATING AND STEM 
CELLS FROM THE KILLER CELLS.  WITH THIS MIXTURE, SHE HAS 
SUCCEEDED IN TRANSPLANTING HUMAN MARROW INTO BABOONS.   BUT SHE 
ACKNOWLEDGES THAT THIS DOES NOT  GUARANTEE THE REVERSE WILL OCCUR
IN THE SAN FRANCISCO AIDS PATIENTS.

                   // OPT ILDSTAD ACTUALITY //

         WE COULD HAVE A NUMBER OF POSSIBILITIES.  WE COULD 
         EITHER HAVE THE HUMAN CELLS STILL BE INFECTABLE AND THE 
         BABOON CELLS  NOT,  OR WE COULD POSSIBLY HAVE AN IMMUNE 
         SITUATION WHICH WOULD BE OBVIOUSLY BE THE OVERALL 
         DESIRED PERFECT OUTCOME -- WHICH PROBABLY WON'T HAPPEN 
         -- WHERE THE BABOON CELLS WOULD ACTUALLY ELIMINATE THE 
         VIRUS.  BUT THAT'S ALL AN UNKNOWN RIGHT NOW.

                // END ACTUALITY // // END OPT //

DR. FRITZ BACH IS  NOT  OPTIMISTIC.  HE IS AN IMMUNOLOGIST WHO 
HEADS TRANSPLANT GROUPS AT HARVARD MEDICAL SCHOOL IN BOSTON AND 
THE VIENNA INTERNATIONAL RESEARCH COOPERATION CENTER IN AUSTRIA.

                      // BACH ACTUALITY // 

        I THINK THAT THE PROBABILITY THAT IN ITS PRESENT FORM 
         THIS WILL FULLY RECONSTITUTE THE IMMUNE SYSTEM OF THE 
         PATIENT BUT THAT MAY BE SOMETHING WHERE WE HAVE TO FIND 
         OUT IS RATHER LOW.  I HAVE CONCERNS -- I'M SURE THAT 
         SUZANNE HAS CONCERNS -- ABOUT HOW LONG THE CELLS WILL 
         SURVIVE.HOW IMPORTANT THAT IS, AND DO WE JUST NEED TO 
         GET THE PATIENT THROUGH A GIVEN PHASE OR WHAT?

                       // END ACTUALITY //

OTHER RESEARCHERS FEAR THAT THE BABOON BONE MARROW TRANSPLANTS 
MAY INTRODUCE VIRUSES HARMLESS TO THE ANIMAL BUT LIFE THREATENING
TO PEOPLE.

DR. ILDSTAD SAYS OTHER SOLUTIONS TO CURB H-I-V HAVE  NOT  WORKED 
AND THAT IT IS TIME TO GIVE AIDS PATIENTS TISSUE WHICH CONTAINS 
GENES NATURALLY RESISTANT TO H-I-V TO SEE IF THAT SOLUTION IS ANY
BETTER.

                   // OPT ILDSTAD ACTUALITY //

         IN A TIME WHEN IT'S NOW BELIEVED THAT VACCINE THERAPY IS
         PROBABLY  NOT  GOING TO BE EFFECTIVE, THE DIFFERENT DRUG
         THERAPIES HAVE  NOT  WORKED, OUR RATIONALE IS TO PERFORM
         A NATURAL FORM OF GENE THERAPY AND ATTEMPT TO ACHIEVE 
         IMMUNE RECONSTITUTION THAT WAY.

                       // END ACTUALITY //

DR. SUZANNE ILDSTAD OF THE UNIVERSITY OF PITTSBURGH, 
PENNSYLVANIA.  (SIGNED)

NEB/DEM/LWM



27-Feb-95 5:43 PM EST (2243 UTC)
NNNN

Source: Voice of America
...........................................................................
--
Jack Woodall, ProMED List Moderator, NY State Dept. of Health, Albany NY
e-mail: woodall at wadsworth.org



More information about the Virology mailing list