CD26: New HIV receptor?

[Ruben Donis]

VIROLOGY NEWS

                              AIDS Daily Summary

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              "Gene Map of AIDS Key Will Help Research--Doctors"
                    Reuters (10/27/93)  (da Silva, Wilson)

     Sydney--Australian scientists say they have cloned and  genetically
mapped the CD26 co-receptor molecule that was  identified only days ago by
French researchers as the key that  allows HIV to enter and infect human
cells.  Geoff McCaughan,  associate professor of Sydney's Royal Prince Alfred
Hospital,  says his research team conducted what they believe is the first
complete mapping of CD26, and the Australian researchers say they will provide
the map to AIDS scientists.  The next step, they  say, is to closely examine
the genetic structure of CD26, in  hopes of revealing a weakness that would
provide insight into the development of a drug able to prevent the AIDS virus
from  invading healthy cells.  If the molecule is indeed the key to HIV
infection, French researchers at the Pasteur Institute suggest  that the
genetic map may allow them "to target these as a way of  reducing the number
of CD26 molecules expressed, thereby reducing the risk of HIV infection," says
McCaughan.  His research team  had been studying the molecule's relationship
with liver disease. After the French researchers' discovery, the Australians
are  trying to match differences in the genetic structure of CD26 with how the
virus affects AIDS patients.  McCaughan says variations  might explain why
some people develop the disease shortly after  infection, some take years, and
others seem to maintain immunity.

                 "Specialists Cast Doubt on New AIDS Findings"
                     Reuters (10/26/93)  (Yanowitch, Lee)

     Marne La Coquette, France--After French researchers at the  Pasteur
Institute claimed on Monday to have solved the mystery of how AIDS penetrates
and infects human cells, the celebration of  the discovery was overshadowed by
the doubts cast by specialists, who said that findings would help understand
the virus, but not  necessarily lead to a vaccine.  Ara Hovanessian, head of
the  Pasteur team, said the researchers had isolated a co-receptor  molecule
called CD26, which serves as a portal allowing the AIDS  virus to invade the
cell.  Hovanessian presented the findings at  a symposium of international
AIDS experts, where many specialists expressed doubt about the use of the
discovery in developing a  vaccine.  "Every discovery must be confirmed by
someone else,"  said Marc Girard, head of vaccine research at the Institute.
"As long as it is not confirmed, it is not valid."  Although Girard  conceded
that perhaps one day a treatment might be developed that could block CD26
activity, it is still not known whether the  molecule has an important or
indispensable function to the human  body.  Another problem with Hovanessian's
research is that there  are cells that HIV may infect via receptors other than
CD4 and  CD26, said Pierre Fillipi, who studies AIDS-generated brain  lesions.
If this held true, CD26 would not be a viable target  for prevention or
treatment.  If, however, later results confirm  Hovanessian's current
hypothesis, scientists could use genetic  manipulation to place CD4 and CD26
receptors on laboratory mice,  thus providing an animal model that AIDS
researchers desperately  need and have long awaited.

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Dr. Ruben Donis                                                 
Dept. of Veterinary and Biomedical Sciences      
202 VBS                                                                    
     
University of Nebraska,                                                  
Lincoln, NE 68583-0905                                   
Phone: 402-472-6063                                     
FAX to 402-472-9690