|
E-mail this page to a friend!
Flu News for Senior Citizens
Flu Vaccine Produced in Insect Cells May Speed
Development in Emergency
Preliminary study finds it safe, successful in
adults; faster than eggs
April 11, 2007 A fear of many involved in
preparing for an outbreak of avian flu and a possible pandemic has been
the dependency on the slow process of developing the influenza vaccines
in chicken eggs. Now, scientists have found a promising alternative to
create vaccine to treat seasonal and pandemic influenza insect cells.
The vaccine produced appeared safe and produced an immunogenic response
in healthy adults in a preliminary study reported in the April 11 issue
of the Journal of the American Medical Association.
All currently licensed influenza vaccines in the
United States are produced in embryonated hens eggs. There are several
well-recognized disadvantages to the use of eggs as the substrate (the
base on which an organism lives or grows) for influenza vaccine. Eggs
require specialized manufacturing facilities and could be difficult to
scale up rapidly in response to an emerging need such as a pandemic,
the authors write.
They add that development of alternative substrates
for influenza vaccine production has been identified as a high-priority.
One potential alternative is use of the influenza virus hemagglutinin
(HA; an antibody that causes red blood cells to clump together) using
recombinant (genetic recombination) DNA techniques.
John J. Treanor, M.D., of the University of
Rochester, N.Y., and colleagues evaluated an experimental influenza
vaccine consisting of recombinant HA expressed in insect cells by a
recombinant baculovirus (rHA0).
The clinical trial was conducted at three U.S.
academic medical centers during the 2004-2005 influenza season and
included 460 healthy adults.
The researchers found: We have shown that the rHA0
vaccine is well tolerated in healthy adults and immunogenic at both
doses evaluated, and we obtained preliminary evidence of protection
against influenza infection and disease. The safety data generated in
this study are consistent with the safety profile observed in previous
studies of rHA0 vaccine. These vaccines have been well tolerated at all
doses administered and are associated with low rates of local
reactions.
The use of recombinant DNA techniques to express
proteins in cell culture has been a successful approach for generation
of highly effective vaccines for the prevention of hepatitis B virus and
human papillomavirus. Among the available expression technologies,
recombinant baculovirus is especially well suited for production of
influenza vaccine because the rapidity with which genes can be cloned
and inserted into this vector facilitates updating the vaccine at
regular intervals.
In addition, the extraordinarily high yields of
protein possible in this system provide the opportunity to use much
higher and potentially more effective doses of vaccine.
Expression of the HA protein in insect cells using
recombinant baculovirus also avoids the need to work with potentially
pathogenic live influenza viruses and the attendant biocontainment
issues that would be a particular concern for generation of pandemic
vaccines.
The preliminary demonstration of protective
efficacy in adults provides further support for the development of this
promising approach for prevention of seasonal and pandemic influenza,
the authors conclude.
Editor's Notes:
Participants were randomly assigned to receive a
single injection of saline placebo (n = 154); 75 μg of an rHA0 vaccine
containing 15 μg of hemagglutinin from influenza A/New
Caledonia/20/99(H1N1) and influenza B/Jiangsu/10/03 virus and 45 μg of
hemagglutinin from influenza A/Wyoming/3/03 (H3N2) virus (n = 153); or
135 μg of rHA0 containing 45 μg of hemagglutinin each from all 3
components (n = 153). Serum samples were taken before and 30 days
following immunization.
Click to More Senior News on the
Front Page
Copyright: SeniorJournal.com |
Peptide blocks flu virus from entering
cells, thwarting its ability to replicate
