Laboratory Tests And Reference Reagents Employed in Studies of Inactivated Hepatitis a Virus Vaccine
Abstract
Procedures to evaluate inactivated hepatitis A vaccines in volunteers have been examined. Solid-phase immunoassays were standardized with reference preparations and have been tested to measure antibody response to immunization and antigen content of vaccines. Following immunization, there was a good correlation between antibody response, determined with commercial immunoassays, and neutralization titres, as measured by the radioimmunofocus inhibition test. However, at lower titres of neutralizing antibody, the commercial immunoassay often yielded negative results. To improve the sensitivity of the immunoassay, the serum volume was increase. A four-fold increase of test serum resulted in greater sensitivity, increasing from 54 to 94%, while retaining 100% specificity. Further increased in the volume of test serum resulted in a loss of specificity. In a comparison of neutralization tests, similar titres of postvaccination serums were obtained by using the HM175/18f cytopathic strain of hepatitis A virus in a plaque reduction assay or the HM175 parental virus in the radioimmunofocus inhibition test. Use of the cytopathic virus obviates the need for radioactively labelled serum and reduces the time taken to conduct neutralization tests. The Current laboratory procedures can meet the needs of large field trials of inactivated hepatitis A vaccines.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1992
- Accession Number
- ADA259295
Entities
People
- C. H. Hoke Jr
- L. N. Binn
- M. H. Sjogren
- P. O. Macarthy
- R. H. Marchwicki
Organizations
- Walter Reed Army Institute of Research