Progenics Discovers First Liver-specific
Receptor for Hepatitis C Virus
Scientists from Progenics Pharmaceuticals may have solved
a longstanding riddle concerning hepatitis C disease: How
does HCV target the liver for infection?
Researchers today reported discovering the first-ever liver-specific
receptor, called L-SIGN, for hepatitis C virus (HCV). The
company also reported the identification of specific inhibitors,
including a monoclonal antibody, which blocked HCV from binding
to the L-SIGN receptor.
Preventing HCV from binding L-SIGN on liver cells represents
a new and targeted strategy for treating this serious disease.
The studies are reported in a paper published today in the
Proceedings of the National Academy of Sciences USA. The publication
is scheduled to be available online this week in the PNAS
"In recent years, various cellular receptors for HCV
have been proposed, but until now, none had been found that
occurred specifically in the liver and was capable of binding
with HCV," said the paper's senior author William C.
Olson, Ph.D., Progenics' Vice President of Research and Development.
"As we reported in today's PNAS article, L-SIGN efficiently
binds and captures naturally occurring hepatitis C virus particles.
We further demonstrated that L-SIGN binds to a viral protein
called E2 that is present on the surface of the HCV particle.
L-SIGN is found on specialized liver cells. These cells are
the first to contact HCV as it enters the liver via the bloodstream.
Thus, L-SIGN is uniquely positioned to capture blood-borne
virus and concentrate it in the liver, thereby potentially
facilitating initial and subsequent rounds of infection."
HCV infection afflicts nearly 3% of the world's population
and causes serious liver disease, including cirrhosis and
cancer. No vaccine is available to prevent new infections.
Current therapies are largely non-specific, effective in only
about half of all cases, and have a high relapse rate. New
treatment strategies are urgently needed to combat this debilitating
The research further demonstrated that HCV bound to a related
receptor, known as DC-SIGN, that is expressed on dendritic
cells, which are specialized cells of the immune system. L-SIGN
and DC-SIGN are also expressed in placental tissue, and thus
the findings may also explain why HCV is readily passed from
mothers to their newborn children."
"Our previous discoveries of the cellular receptors
utilized by HIV have translated directly into novel therapeutic
agents, and we are eager to leverage this expertise for HCV
therapy," added Dr. Olson.
"We have shown that HCV binding to L-SIGN can be blocked
in the laboratory using specific inhibitors, including monoclonal
antibodies. In addition, HCV appears to bind L-SIGN at a site
different from that of its natural ligand (ICAM-3), which
is a protein that mediates adhesion between cells.
"Thus, it may be possible to block HCV without blocking
the natural activity of L-SIGN. These findings provide proof-of-concept
for targeted therapy. Our current goals are to develop increasingly
potent and drug-like inhibitors while concurrently exploring
the role of L-SIGN in natural infection."
Progenics Pharmaceuticals, Inc. of Tarrytown, NY, is a biopharmaceutical
company focusing on the development and commercialization
of innovative therapeutic products to treat the unmet medical
needs of patients with debilitating conditions and life-threatening
The Company applies its expertise in immunology and molecular
biology to develop biopharmaceuticals to fight viral diseases,
such as human immunodeficiency virus (HIV) infection, and
cancers, including malignant melanoma and prostate cancer.
In symptom management and supportive care, therapies are being
developed to provide patients with an improved quality of
life. Progenics' most clinically advanced product is methylnaltrexone,
a compound in phase-3 clinical testing that is designed to
block the debilitating side effects of opioid analgesics without
interfering with pain palliation.
The Company is conducting multi-dose phase-2 clinical trials
with its lead HIV product, PRO 542, a viral-entry inhibitor
and is in preclinical development with PRO 140 and other follow-on
product candidates in HIV infection. The Company is developing
cancer immunotherapies based on PSMA (prostate-specific membrane
antigen) technology and currently is conducting phase-1 clinical
studies of a therapeutic prostate cancer vaccine. GMK is a
cancer vaccine in phase-3 clinical trials for the treatment
of malignant melanoma.
This letter was written by a drug
attempting to get people to invest in there stock.
This info is flawed. One item that stands out is the reference
to "HCV readily passed to children". This is an
extreme exaggeration. Less than one percent pass the virus
to children and this is almost always because of blood transfer
The items discussed are pointed to the liver and only the
HCV uses the pancreas as an alternate breeding ground and
most likely many other sites. This info was known in 1994.
This company is really reaching.
Your immune system is your best bet.
15 to 20% of all people with hep c do not develop chronic
liver disease (CDC) because there immune system fights off
the disease. Most of the rest of us can do this at least enough
to regain our health by boosting our immune system.
My statement has not been reviewed by