Research On The HBV Intrauterine Transmission And Nucleotide Changes In HBV S Fragment Before And After Inoculation

Objective To illvestigate the prevalence rate ot?1113V intrauterine infection and the prophylactic inoculation effect with combination of 1-[BIG and UBvac to prevent or interrupt L-LBV vertical transmission, then assort the HBV genotypes between the mothers and their newborns. Comprehend the character of the molecular epidemiology of?the virus gene mutation. To understand the immune reaction and biological mechanism that may explain why many neonates fail to be protected from 1-IBV infection, even though they have been actively and passively inoculated.Methods Through cross and cohort study, we collect blood sample from the newborn and babies at different age and mother during perinatal period. Peripheral vein blood was obtained from 135 women with LIBsAg positive and 139 new-burns (including 4 pairs of twins) of those special mothers were also phlebotomized. Another 25 pairs of mother and infants were let blood as control group at the same time. Sera HBV markers were detected by EL1SA and S fragment of HBV-DNA by nested-PCR. Respectively restrictive enzyme of Bsrl, Styl, Dpnl and Hpall act on the amplified gene and compare the restrictive fragments length polymorphism (RFLP) to determine the HBV genotype. 6 samples of C genotype 6 B genotype samples and 1 D genotype samples with another 10 controls were amplified(nt 401-833) cloned, sequenced and analyzed. Results All togethet we collected 139 pairs of mother and newborn blood samples, and 88 cases were follow-up, including some of the original samples, the rate of HBV intrauterine infection is 5.4%(7/130), and 12.4%(6146) for the HBeAg positive mother's babies. Even though the prophylactic method, three doses of hepatitis B vaccine within 24 hours afier birth, one month and six months of age, respectively, is very etiective; the prophylactic effect of combination of twice HBIG and 3 [lBvac is niore significant. The genotype of l-IBV materanal-infant transmission-3-transmitted. The homology of I-IBV nucleotide and amino acid sequences in the mothers and their fetuses was over 98.5%. There are many base mutations in HBV S fragment, most in the ?a -determinant, however some also appeared in the outside of the ?a ?-determinant. The main amino acid(Ai\) alterations include 126 Pro梸Thr, 142 Pro梑 Met, 200ThrlThe, l96Trp?Leu/Ser. immune pressure cause the 587 nt G桝, leading the l45Gly梸Arg.Conclusion [IBV transmission can take place in utera. The prophylactic project of combination HBvac and f-IBIG is very effective, but many infants still can抰 be protected and the detected infection during newborns period can be comprehended as intrauterine infection. Base mutation becomes more frequent and unstable under immune pressure with FTBIG and HBvac. The base change of HBV-DNA taking place in the newborns can appear in the mother blood samples.