Long-Term Excretion of Vaccine-Derived Poliovirus by a Healthy Child
AUTOR(ES)
Martín, Javier
FONTE
American Society for Microbiology
RESUMO
A child was found to be excreting type 1 vaccine-derived poliovirus (VDPV) with a 1.1% sequence drift from Sabin type 1 vaccine strain in the VP1 coding region 6 months after he was immunized with oral live polio vaccine. Seventeen type 1 poliovirus isolates were recovered from stools taken from this child during the following 4 months. Contrary to expectation, the child was not deficient in humoral immunity and showed high levels of serum neutralization against poliovirus. Selected virus isolates were characterized in terms of their antigenic properties, virulence in transgenic mice, sensitivity for growth at high temperatures, and differences in nucleotide sequence from the Sabin type 1 strain. The VDPV isolates showed mutations at key nucleotide positions that correlated with the observed reversion to biological properties typical of wild polioviruses. A number of capsid mutations mapped at known antigenic sites leading to changes in the viral antigenic structure. Estimates of sequence evolution based on the accumulation of nucleotide changes in the VP1 coding region detected a “defective” molecular clock running at an apparent faster speed of 2.05% nucleotide changes per year versus 1% shown in previous studies. Remarkably, when compared to several type 1 VDPV strains of different origins, isolates from this child showed a much higher proportion of nonsynonymous versus synonymous nucleotide changes in the capsid coding region. This anomaly could explain the high VP1 sequence drift found and the ability of these virus strains to replicate in the gut for a longer period than expected.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=533926Documentos Relacionados
- Long-Term Circulation of Vaccine-Derived Poliovirus That Causes Paralytic Disease
- Excretion of Wild-Type and Vaccine-Derived Poliovirus in the Feces of Poliovirus Receptor-Transgenic Mice
- Prolonged Replication of a Type 1 Vaccine-Derived Poliovirus in an Immunodeficient Patient
- Circulation of Type 1 Vaccine-Derived Poliovirus in the Philippines in 2001
- Evolution of Circulating Wild Poliovirus and of Vaccine-Derived Poliovirus in an Immunodeficient Patient: a Unifying Model