Comparative sequence analysis of the P-, M- and L-coding region of the measles virus CAM-70 live attenuated vaccine strain

Abstract

Measles virus is a highly contagious agent which causes a major health problem in developing countries. The viral genomic RNA is singlestranded, nonsegmented and of negative polarity. Many live attenuated vaccines for measles virus have been developed using either the prototype Edmonston strain or other locally isolated measles strains. Despite the diverse geographic origins of the vaccine viruses and the different attenuation methods used, there was remarkable sequence similarity of H, F and N genes among all vaccine strains. CAM-70 is a Japanese measles attenuated vaccine strain widely used in Brazilian children and produced by Bio-Manguinhos since 1982. Previous studies have characterized this vaccine biologically and genomically. Nevertheless, only the F, H and N genes have been sequenced. In the present study we have sequenced the remaining P, M and L genes (approximately 1.6, 1.4 and 6.5 kb, respectively) to complete the genomic characterization of CAM-70 and to assess the extent of genetic relationship between CAM-70 and other current vaccines. These genes were amplified using long-range or standard RT-PCR techniques, and the cDNA was cloned and automatically sequenced using the dideoxy chain-termination method. The sequence analysis comparing previously sequenced genotype A strains with the CAM-70 Bio-Manguinhos strain showed a low divergence among them. However, the CAM-70 strains (CAM-70 Bio-Manguinhos and a recently sequenced CAM-70 submaster seed strain) were assigned to a specific group by phylogenetic analysis using the neighbor-joining method. Information about our product at the genomic level is important for monitoring vaccination campaigns and for future studies of measles virus attenuation.

Study of the genetic stability of measles virus CAM-70 vaccine strain after serial passages in chicken embryo fibroblasts primary cultures

“…Previous genetic analyses of coding regions of CAM-70 have considered this vaccine the most divergent member within its clade [21,31]. Our analysis comparing the full genome of CAM-70 with that of other measles vaccines confirms this observation.…”

“…Since, the occurrence of nucleotide heterogeneities in measles virus genomic sequences has never been reported, our discussion is limited by the paucity of data on this matter. Notwithstanding, it is important to emphasize the limitation of genome analysis by direct sequencing which is There are three nucleotide differences in the H gene when comparing with the sequence of Rota and coworkers [21], and two nucleotides differences in the P gene when comparing with the sequence of Santos and co-workers [31] (Table 1). In fact, both studies have used a few passages of the CAM-70 virus in Vero cells to obtain the stock used for RNA extraction and cDNA synthesis.…”

Altered Interaction of the Matrix Protein with the Cytoplasmic Tail of Hemagglutinin Modulates Measles Virus Growth by Affecting Virus Assembly and Cell-Cell Fusion

“…Therefore, the original isolates would have had to spread many times in some way via SLAM-and CD46-independent mechanisms. Available sequence data indicate that all MV vaccine strains have both or either of the P64S and E89K substitutions (32,38,39) (GenBank accession number EF033071). We speculate that at least one of these substitutions is needed for MV to survive in unnatural host cells.…”

“…P64S and E89K substitutions were shown to be responsible for the ability of the Edmonston M protein to enable the virus to grow efficiently in Vero cells at postentry steps (45). Examination of published sequence data revealed that all MV vaccine strains have either or both of the P64S and E89K substitutions in their M proteins (32,38,39) (GenBank accession number EF033071).…”

Genetic characterization of Chinese measles vaccines by analysis of complete genomic sequences

“…In order to describe the genetic changes that accompany attenuation, the sequences of the genomes of the measles vaccine strains have been compared [Rota et al, 1994;Bankamp et al, 1999Bankamp et al, , 2005Parks et al, 2001a,b;Bankamp et al, 2002;Santos et al, 2003;Liu et al, 2006]. Though partial sequence comparisons were conducted [Rota et al, 1994;Bankamp et al, 2005], the complete genomic sequences of the Chinese vaccines, S-191 and C-47, have not been analyzed.…”