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Background Previous studies have suggested that mother-to-child transmission of HIV-1 is often characterized by acquisition of a homogeneous viral quasispecies in the infant, suggestive of a genetic bottleneck. In this study, we have analyzed the molecular characteristics of transmitted HIV-1 viruses in a homogeneous population infected by CRF01_AE variants in Thailand. Materials and methods Seventeen mother-child pairs were studied. The infants were not breastfed. Six infants were infected in utero and 11 infants were infected intrapartum. The env sequences covering the entire gp120 were amplified from both the proviral DNA of maternal PBMC collected at delivery and the plasma viral RNA at first positive time point of infants. The amplified products were cloned and sequenced. A total of 353 clones were available for analysis. Results Phylogenetic analysis indicated 2 patterns of transmission: 14 mothers transmitted a single variant and 3 mothers transmitted multiple variants to their infants. The mean genetic distance of viruses from the mothers was significantly higher than those from the infants (2.7% vs. 0.6%; P<0.01), but without any difference according to timing of transmission, either in utero or intrapartum. The length of gp120 and number of potential N-linked glycosylation sites (PNGS) were similar in both the entire gp120 and individual regions of gp120 of all motherchild pairs. However, our data indicate that 4 PNGS positions (N241, N301, N354, and N384) that appeared conserved in all infant variants but were irregularly present in the mothers might be associated to a selective advantage. In addition, we report the first case to our knowledge of transmission to an infant of a recombinant virus issued from variants from his mother. Conclusions Our results provide additional evidence that despite a complex viral population in the mother, only viruses of a restricted subset are transmitted to the infant, independently of the timing of transmission, in utero or intrapartum. We did not find that shorter gp120 or fewer PNGS were characteristics of viruses transmitted from mother to infant, as it was suggested for sexually transmitted viruses at least for a few subtypes. Four PNGS were selected for transmitted viruses, supporting the role of the "glycan shield" of the HIV-1 envelope in conferring a selective advantage. [ABSTRACT FROM AUTHOR]

Background: Despite implementation of universal infant hepatitis B (HB) vaccination, mother-to-child transmission (MTCT) of hepatitis B virus (HBV) still occurs. Limited data are available on the residual MTCT of HBV in human immunodeficiency virus (HIV)-HBV co-infected women., Objectives: We assessed the prevalence of HBV infection among HIV-infected pregnant women and the rate of residual MTCT of HBV from HIV-HBV co-infected women and analyzed the viral determinants in mothers and their HBV-infected children., Study Design: HIV-1 infected pregnant women enrolled in two nationwide perinatal HIV prevention trials in Thailand were screened for HB surface antigen (HBsAg) and tested for HBeAg and HBV DNA load. Infants born to HBsAg-positive women had HBsAg and HBV DNA tested at 4-6 months. HBV diversity within each HBV-infected mother-infant pair was analyzed by direct sequencing of amplified HBsAg-encoding gene and cloning of amplified products., Results: Among 3312 HIV-1 infected pregnant women, 245 (7.4%) were HBsAg-positive, of whom 125 were HBeAg-positive. Of 230 evaluable infants born to HBsAg-positive women, 11 (4.8%) were found HBsAg and HBV DNA positive at 4-6 months; 8 were born to HBeAg-positive mothers. HBV genetic analysis was performed in 9 mother-infant pairs and showed that 5 infants were infected with maternal HBV variants harboring mutations within the HBsAg "a" determinant, and four were infected with wild-type HBV present in highly viremic mothers., Conclusions: HBV-MTCT still occurs when women have high HBV DNA load and/or are infected with HBV variants. Additional interventions targeting highly viremic women are thus needed to reduce further HBV-MTCT., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Approximately 4 million of people are co-infected with HIV and Hepatitis B virus (HBV). In resource-limited settings, the majority of HIV-infected patients initiate first-line highly active antiretroviral therapy containing lamivudine (3TC-containing-HAART) and long-term virological response of HBV to lamivudine-containing HAART in co-infected patients is not well known., Methodology/principal Finding: HIV-HBV co-infected patients enrolled in the PHPT cohort (ClinicalTrials.gov NCT00433030) and initiating a 3TC-containing-HAART regimen were included. HBV-DNA, HIV-RNA, CD4+ T-cell counts and alanine transaminase were measured at baseline, 3 months, 12 months and then every 6 months up to 5 years. Kaplan-Meier analysis was used to estimate the cumulative rates of patients who achieved and maintained HBV-DNA suppression. Of 30 co-infected patients, 19 were positive for HBe antigen (HBeAg). At initiation of 3TC-containing-HAART, median HBV DNA and HIV RNA levels were 7.35 log(10) IU/mL and 4.47 log(10) copies/mL, respectively. At 12 months, 67% of patients achieved HBV DNA suppression: 100% of HBeAg-negative patients and 47% of HBeAg-positive. Seventy-three percent of patients had HIV RNA below 50 copies/mL. The cumulative rates of maintained HBV-DNA suppression among the 23 patients who achieved HBV-DNA suppression were 91%, 87%, and 80% at 1, 2, and 4 years respectively. Of 17 patients who maintained HBV-DNA suppression while still on 3TC, 4 (24%) lost HBsAg and 7 of 8 (88%) HBeAg-positive patients lost HBeAg at their last visit (median duration, 59 months). HBV breakthrough was observed only in HBeAg-positive patients and 6 of 7 patients presenting HBV breakthrough had the rtM204I/V mutations associated with 3TC resistance along with rtL180M and/or rtV173L., Conclusions: All HBeAg-negative patients and 63% of HBeAg-positive HIV-HBV co-infected patients achieved long-term HBV DNA suppression while on 3TC-containing-HAART. This study provides information useful for the management of co-infected patients in resource-limited countries where the vast majority of co-infected patients are currently receiving 3TC.

Mother-to-child transmission (MTCT) of HIV-1 provides a model for studying the role of passively acquired antibodies in preventing HIV infection. We determined the titers of neutralizing antibodies (NAbs) against six primary isolates of clades B and CRF01&#95;AE in sera from 45 transmitting and 45 nontransmitting mothers matched for the main independent factors associated with MTCT in Thailand. A lower risk of MTCT, particularly for intrapartum transmission, was associated only with higher NAb titers against the CRF01&#95;AE strain, MBA. The envelope glycoprotein of this strain showed an unusually long V2 domain of 63 amino acids, encoding six potential N-linked glycosylation sites. We provided experimental data indicating that the extended V2 domain contributed to the higher level of resistance to neutralization by mothers' sera in this strain. Taken together the data suggest that some primary isolates with specific properties may be useful indicators for identifying protective antibodies.