Studies on the Pathogenesis of Hepatitis A and Feasibility Studies on a Hepatitis A Vaccine.
Annual rept. 15 Jan 86-14 Jan 87,
UTAH UNIV SALT LAKE CITY SCHOOL OF MEDICINE
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The objectives of this work are to further our knowledge of the pathogenesis of hepatitis A virus HAV infection in man, and to develop recombinant expression vectors for HAV antigens that can be used to stimulate mucosal immunity. Viral cDNA sequences encoding the viral capsid protein, VP1, have been cloned into several bacterial expression vector plasmids, and in one case, efficient production of a fusion protein containing VP1 sequences has been obtained. This fusion protein has been partially purified and used to induce antiserum in a rabbit. The resulting antibodies react with VP1 from purified virions, but do not immunoprecipitate or neutralize intact virus. The immunized rabbit, however, appeared to produce a secondary, anamnestic response to challenge with a sub-immunogenic dose of intact virus. Additional plasmid constructions have been designed to express other forms of VP1 protein and are currently under development. An in situ hybridization procedure has been developed, using probes prepared for our cloning studied. This procedure detects HAV-infected cultured cells with high sensitivity, and has been successfully applied to the analysis of liver biopsy material from HAV-infected Aotus monkeys, provided by Walter Reed. We have developed a dot blot hybridizaiton test to evaluate the course of infection in cultured cells.
- Medicine and Medical Research