engleski

Determination of the coding and noncoding nucleotide sequence of original Edmonston-Zagreb master seed and current working seed lot.

To confirm the genetic stability of Edmonston-Zagreb vaccine strain we determined and compared the nucleotide sequences of genuine Edmonston-Zagreb master seed (EZ D22) and current working seed lot (EZ D24 2/99) produced and stored in Institute of Immunology Inc., Zagreb. Sequence analysis of EZ D22 and EZ D24 2/99 and comparison of two sequences confirmed at molecular level that the noncoding sequences and protein-encoding nucleotide sequences of the N, P, M, F, H and L genes are the same. In addition, the obtained sequences were compared to reference strains, i.e. Edmonston wild type (Edmonston Wt) AF266288 and Edmonston-Zagreb (EZ) AF266290 vaccine strain. The sequence of genuine Edmonston-Zagreb master seed (EZ D22) differed from the Edmonston Wt (AF266288) in 32 nucleotides. Nine substitutions were in the noncoding and 23 were in the coding region. In comparison to EZ (AF266290) sequence, EZ D22 differs in 6 nucleotides, one in the noncoding region and 5 in the coding region. Coding substitution at position 441 and two silent substitutions at positions 11999 and 14612 in the L gene are unique for genuine Edmonston-Zagreb master seed (EZ D22). Partial sequence analysis showed that limited passaging of measles virus (EZ D24 2/99) on Vero cells did not affect consensus sequence determinations. The differences found between EZ from different sources could be a good reason for periodical sequence analysis of the same strain in hands of different manufactures and comparison of the obtained sequences to the genuine strain, as these mutations could affect the safety and efficacy of the vaccine.

measles vaccine

nije evidentirano