Fera Ibrahim

Antigenic differences between wildtype measles viruses and vaccine viruses in Indonesia

Measles virus has a single, negative strand RNA genome which codes 6 structural proteins: N, F, P, M, H and L. Currently there are several variances in the nucleotide sequences of N, F, M and H genes across wild type measles viruses, hence measles viruses can be categorized into clades and genotypes. The antigenicity of the previous genotype of measles is different from the current genotype. Objective To determine the antigenic differences between wild type measles virus and measles vaccine virus. Methods Analysis of the antigenic differences between wild type virus (G2, G3 and D9) and vaccine virus (CAM-70 and Schwarz) was performed by immunizing mice with the respective viruses. The serum was then tested with micro-cross-neutralization technique using the G2, G3, D9 and CAM-70 virus. Tests with cross ELISA examination technique were also performed using the same set of virus. Results Analysis of the cross neutralization test and cross ELISA showed that the highest antigenicity reaction was found between wild type virus with antibody against wild type virus, while the lowest reaction was between wild type virus with antibody against CAM-70. Conclusions We conclude that the antigenicity of antigenic protein from wild type virus is higher than antigenicity of vaccine virus protein. In addition, it was found that the antigenicity of proteins from Schwarz vaccine virus was higher than proteins CAM-70 vaccine virus. (Paediatr Indones 2008;48:125-35).

Antigenic Variation in H5N1 clade 2.1 Viruses in Indonesia From 2005 to 2011

Influenza A (H5N1) virus, has spread to several countries in the world and has a high mortality rate. Meanwhile, the virus has evolved into several clades. The human influenza A (H5N1) virus circulating in Indonesia is a member of clade 2.1, which is different in antigenicity from other clades of influenza A (H5N1). An analysis of the antigenic variation in the H5 hemagglutinin gene (HA) of the influenza A (H5N1) virus strains circulating in Indonesia has been undertaken. Several position of amino acid mutations, including mutations at positions 35, 53, 141, 145, 163, 174, 183, 184, 189, and 231, have been identified. The mutation Val-174-Iso appears to play an important role in immunogenicity and cross-reactivity with rabbit antisera. This study shows that the evolution of the H5HA antigenic variation of the influenza A (H5N1) virus circulating in Indonesia from 2005 to 2011 may affect the immunogenicity of the virus.