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BIOGRAPHY:
Dr. ter Meulen received his M.D. in 1988 from the Albert-Ludwig University Medical School in Freiburg, Germany. He earned his Dr.Med. in epidemiology in 1990 from Julius Maximilian University in Würzburg, Germany. He conducted research from 1988 until 1992 at the German Cancer Research Center. He held positions at the Bernhard Nocht Institute for Tropical Medicine, and from 1988 until 1999 worked as Research Scientist at EPICENTRE (Groupe Européen d'Expertise en Épidémiologie Pratique) in Paris, France. He is currently Research Scientist of the Projet de Recherche sur les Fièvres Hémorragiques en Guinée at the University of Conakry Institute for Microbiology in Guinea. He is also currently Research Scientist in the Department of Virology of the Bernhard Nocht Institute for Tropical Medicine. His HHMI-funded project is entitled "Mapping of Neutralizing Epitopes on Domain I of the Yellow Fever Virus Envelope Glycoprotein with Recombinant Human Antibodies Generated Through Phage Display."
RESEARCH ABSTRACT SUMMARY:
Mapping of Neutralizing Epitopes on Domain I of the Yellow Fever
Virus Envelope Glycoprotein with Recombinant Human Antibodies Generated
Through Phage Display
Yellow fever virus (YFV) is a mosquito-transmitted, enveloped
positive-stranded RNA virus belonging to the genus Flavivirus,
family Flaviviridae. It causes hemorrhagic fever in humans in Africa
and South America. Epidemics of yellow fever (YF) have been occurring
with increasing frequency in recent years, with a lethality of about 25
percent. Humoral immunity follows natural YFV infection and
immunization with the live attenuated YFV vaccine strain 17D. For
humans, the neutralizing epitopes on the virus have not been mapped. In
the present study, we constructed two phage libraries displaying human
antibody scFv fragments using lymphocytes of two donors who recovered
from YF during the 2000 YF outbreak in Guinea, West Africa. To isolate
scFvs with specific affinity for YFV, we panned the phage libraries
with purified YF 17D virions. Six monoclonal phages with high affinity
for the YF 17D virus were isolated. The six different scFv displayed by
the monoclonal phages were expressed as soluble molecules and
precipitated the YFV envelope glycoprotein (E protein) in a
radioimmunoprecipitation assay. Three scFv neutralized YFV 17D in a
Plaque Reduction Neutralization Test (PRNT). To map the neutralizing
epitopes on the YFV-E protein, viral escape mutants of the 17D YFV
strain were generated under selective pressure of the respective scFv.
Sequencing analysis of these variants identified single amino acid
substitutions on domain I of the E protein at positions aa 153 and 154.
Because the epitopes were mapped with recombinant antibodies generated
from wild-type YFV–infected patients, we believe that we have
identified the domains on the 17D vaccine strain of YFV responsible for
inducing protective humoral immunity in humans.
Photo: Kent Kallberg, Kallberg Studios
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