[Press Kit, International Conference on AIDS (13th : 2000 : Durban, South Africa)]

"Plantibodies" represent an innovative approach to microbicide development using genetically
engineered plants to produce human antibodies active against HIV and other STIs. Antibodies are
one of the body's main defense systems, and the basis for vaccine technology. Today, scientists
have found ways to isolate the particular antibodies that counteract HIV and other STIs, and to mass
produce them-- relatively inexpensively-- using genetically engineered plants. This technology raises
the possibility of delivering anti-HIV antibodies directly to the vagina, allowing them to combat
pathogens before actual infection occurs.
PMPA Gel works in the same way as some of the anti-retroviral drugs currently used for therapy: it
interrupts the replication of the virus once it enters cells. The hope is that PMPA could be absorbed
by cells in the vaginal epithelium and then stop the virus in its tracks once it enters the outer cells of
the vaginal wall. Many anti-retroviral drugs that were initially explored as potential AIDS therapies
were later abandoned because they could not be absorbed easily into the bloodstream; these same
compounds might be perfect candidates for a microbicide because they could be topically applied
and not absorbed systemically.
Pro-2000 Gel contains a synthetic polymer that binds to the HIV virus, thereby disrupting binding of
the virus to target cells. The gel probably works in a similar fashion to block chlamydia and HSV-2
infections.
The first priority of research is to get a safe and effective microbicide available as soon as
possible. However, it is important to understand that the differences between and among various
product leads may determine how they might be used and by whom. Some product concepts are
based exclusively on the ecology of the vagina; others could potentially offer protection from
rectal transmission as well. Product development must be accompanied by further research in
vaginal and rectal ecology, mucosal immunity, rectal safety, and user formulation preferences in
order to maximize the potential benefit of microbicides for many people.
Number of Product Leads Under Development,
1994-1999
0 5 10 15 20 25 30 35
Pre-clinical1999
U119981I
Early Clinical i I
Phase III
Source: Alliance for Microbicide Development, 1999.
For more information and/or descriptions of other products, see the Alliance for Microbicide Development
Webpage at http//www.microbicide.org.

Global Campaign for STI/HIV Prevention Alternatives for Women, Takoma Park, MD, July 2000. For info. contact [email protected]