Evolution of hepatitis C virus quasispecies in mothers and infants infected through mother-to-infant transmission.
OBJECTIVE
Two mother-infant pairs (Pair H and P) were studied to determine the evolution of hepatitis C virus (HCV) quasispecies.


METHODS
Eight clones of the hypervariable region of HCV cDNA from the infants' sera sampled at the age of 3 months, 1, 2, and 3 years and the time-corresponding maternal sample were also sequenced. The sequences were analyzed by the nucleotide diversity, substitution rate, and phylogenetic studies.


RESULTS
HCV quasispecies of the infants were more homogeneous than those of their mothers, particularly at the age of 3 months (nucleotide diversity, pi = 0.18 x 10(-2)/site in infant H, and 0.22 x 10(-2)/site in infant P). The nucleotide substitution rate in infants also increased as they aged, from 1.2 x 10(-2) to 4.46 x 10(-2)/site/year in infant H, and from 0.21 x 10(-2) to 4.88 x 10(-2)/site/year in infant P respectively. The nucleotide sequence differences between infants and mothers increased from 2.63 x 10(-2) to 9.06 x 10(-2)/site in Pair H, and from 1.85 x 10(-2) to 5.33 x 10(-2)/site in Pair P within 3 years. Phylogenetic studies suggest the infants' initial quasispecies were closely related to their mothers', while they evolved differently. HCV RNA titer was stable during follow-up and the infants' titer was similar to their mothers'. The fluctuations in titer did not correlate with nucleotide diversity.


CONCLUSIONS
HCV quasispecies evolved differently in each individual, even though they were genetically linked. The sequence in infants was not a complex as in their mothers.
Ni
Y H
YH
Department of Pediatrics, Graduate Institute of Clinical Medicines, National Taiwan University, Taipei.
Chang
M H
MH
Chen
P J
PJ
Lin
H H
HH
Hsu
H Y
HY
D000328:Adult; D001483:Base Sequence; D005075:Biological Evolution; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D014644:Genetic Variation; D016174:Hepacivirus / Q000235:genetics*; D006526:Hepatitis C / Q000635:transmission*; D006801:Humans; D007223:Infant; D008969:Molecular Sequence Data; D009035:Mothers; D010802:Phylogeny; D012367:RNA, Viral / Q000032:analysis; D013997:Time Factors
D018076:DNA, Complementary; D012367:RNA, Viral