The content of 472U to 472C revertant virus in serotype 3 oral poliomyelitis monovalent bulk vaccines can be quantified by MAPREC (Mutant Analysis by PCR and Restriction Enzyme Cleavage). Besides other wildtype reversions identified in propagated type 3 Sabin strain populations, the 472U to 472C reversion correlates most prominently with neurovirulence in the monkey neurovirulence test. Therefore, the results can be used for the discrimination of 'good' and 'bad' vaccines on the molecular level. In international collaborative studies it has been well established that vaccine lots containing revertant genomes below a critical threshold pass the in vivo monkey neurovirulence test (MNVT), while vaccine lots containing more revertants fail the MNVT. In this communication we show that the MAPREC test is a sensitive tool for quality control and the demonstration of consistency in large scale production. Furthermore, MAPREC offers a possibility to assess the effect of changed production conditions on the rate of reversion and to find conditions for consistent production with low reversion rates.
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http://dx.doi.org/10.1016/s0264-410x(99)00531-9 | DOI Listing |
Vaccines (Basel)
January 2025
Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD 20993, USA.
Background/objectives: Conventional live oral poliovirus vaccines (OPVs) effectively prevent poliomyelitis. These vaccines are derived from three attenuated Sabin strains of poliovirus, which can revert within the first week of replication to a neurovirulent phenotype, leading to sporadic cases of vaccine-associated paralytic poliomyelitis (VAPP) among vaccinees and their contacts. A novel OPV2 vaccine (nOPV2) with enhanced genetic stability was developed recently; type 1 and type 3 nOPV strains were engineered using the nOPV2 genome as a backbone by replacing the capsid precursor polyprotein (P1) with that of Sabin strains type 1 and type 3, respectively.
View Article and Find Full Text PDFIntroduction: Rabies continues to be a significant concern in India, with lots of deaths reported annually. Approximately one million people undergo post-exposure prophylaxis treatment annually, despite nearly two million dog bites occurring across the country. Notably, dogs are responsible for more than 99% of these bites.
View Article and Find Full Text PDFPharmeur Bio Sci Notes
December 2024
European Directorate for the Quality of Medicines & HealthCare, Department of Biological Standardisation, OMCL Network & HealthCare (DBO), Council of Europe, Strasbourg, France.
Hum Vaccin Immunother
December 2024
Department of Microbiology, College of Medicine, Yeungnam University, Daegu, Republic of Korea.
The COVID-19 pandemic forced the rapid development of methods to measure humoral and cellular immunity against SARS-CoV-2. The lack of a global standardized protocol and the high variability of intra- and inter-assay precision of the T-cell response made it difficult to compare T-cell assay results with those of other laboratories. The interferon-gamma enzyme-linked immunosorbent spot (IFN-γ ELISpot) assay for immunogenicity evaluation was validated using naturally infected donor peripheral blood mononuclear cells, a commercially available IFN-γ ELISpot kit, and a SARS-CoV-2 specific peptide pool.
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