Genomic and biological characterization of the measles virus cepa vaccine CAM-70.
Bio-Manguinhos has the competence for producing a measles vaccine using the Biken CAM-70 strain. Since the Ministry of Health adopted the MMR vaccine for vaccinationcampaigns, the production of the monovalent measles vaccine was discontinued. However, the export potential of a monovalent measles vaccine justifies the restart of production.Therefore, the genomic and biological characterization of this vaccine virus may greatly contribute to the introduction of improvements in the production process and in providingdata for the knowledge of our product. To evaluate the genetic stability of the CAM-70 measles vaccine strain we haveperformed ten serial passages of the seed lot virus FMS-7 in chicken embryo fibroblasts primary cultures (CEF) under production conditions. The nucleotide sequences of the seed lotvirus, the virus from a vaccine vial (third passage) and from the tenth passage were determined and compared with each other and with all available measles vaccine sequences.The results obtained for the seed virus FMS-7, for the virus from a vaccine lot (third passage) and passage ten have revealed identical genomic sequences and demonstrate that the measles CAM-70 vaccine virus is highly adapted to its cultivation conditions and genetically stableunder these conditions. In this study we have also investigated the influence of interferon (IFN) in virus yields. CEF cultures in high density (HD) and low density (LD) were inoculated with theCAM-70 virus and collected daily for up to 10 days. The suspensions originated from these cultures were titrated in a test for IFN detection and evaluated for the expression of theenzyme 2-5 oligoadenilate synthetase (2-5OAS). The CAM-70 virus was able to induce the production of IFN in CEF as demonstrated by the IFN titration assays and the expression of 2-5 OAS. The observation of higher virus titers in LD cultures suggests that this virus is sensitive to IFN. IFN results recommend the production of vaccine in LD cultures for the achievement of higher virus yields. This study also demonstrates that the CAM-70 virus is highly stablefrom the genetic point of view, under production conditions. This stability allows the extension of the use of the seed lots and contributes for the safety profile of the measlesvaccine manufactured with the CAM-70 strain.
Advisor:Ricardo Galler; Akira Homma
School:Faculdades Oswaldo Cruz
Source Type:Master's Thesis
Keywords:Measles virus Fibroblasts Genomics
Date of Publication:12/18/2007