Lack of protection against vertical transmission of HIV-1 by interferons produced during pregnancy in a cohort from East African republic of Malawi

Characterization of the main placental cytokine profiles from HIV-1-infected pregnant women treated with anti-retroviral drugs in France

Cytokines are involved in regulating HIV-1 infection. They are also placental environment major components. We assessed the potential impact of HIV-1 infection and/or anti-retroviral drugs on the placental cytokine profiles that may be involved in controlling HIV-1 placental dissemination. Placental explants were obtained after elective caesarean section from anti-retroviral-treated HIV-1-infected pregnant women and from HIV-1 non-infected pregnant women. The main placental cytokines were assessed for protein secretion in the supernatants of 24-h placental culture explants and/or in uncultured placental explants for mRNA expression levels. The cytokine profiles were different between the HIV-1-infected and the non-infected groups. Higher medians of leukaemia inhibiting factor (LIF), tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 secretion were found in the 24-h culture supernatant of term placenta from HIV-1-infected women. High median levels of IL-16 and regulated upon activation normal T cell expressed and secreted (RANTES) levels were found in both groups. The mRNA expression medians were lower for TNF-alpha and IL-8 and higher for stromal cell-derived factor-1 (SDF-1) in uncultured placental explants from HIV-1-infected women. In the HIV-1-infected group, but not in the non-infected group, the secretion levels of TNF-alpha and IL-8, as well as their mRNA expression levels, were highly positively correlated; furthermore, their secretion levels were correlated positively with LIF and IL-10 secretion levels. We found no correlation between the cytokine levels and the immunovirological status of the HIV-1-infected mothers or the type or duration of treatment. These results highlight the potential impact of HIV-1 and of the anti-retroviral treatments on the placental cytokines pattern, independently of their anti-viral activity.

Pathogenesis of transplacental virus infection: pestivirus replication in the placenta and fetus following respiratory infection

Although transplacental virus infections account for considerable morbidity and mortality in both animals and humans, very little is so far known about the pathways whereby virus reaches the conceptus, the subsequent virus-host interactions in the early phases of the infections, and the establishment of persistent non-lethal infection. Using a natural animal model we recently demonstrated that bovine pestivirus can spread from the site of infection to the ovine fetus within 72 h, despite the expression of interferon in the reproductive tract [1]. In the present study we demonstrate that pestivirus first establishes infection and spread within the allantoic and amniotic membranes and then the fetus, followed several days later by infection of the uterine glands. However, virus replication and spread within the fetus is, at least in part, controlled by fetal developmental factors. In fetuses less than 25 days of gestational age, the virus remains restricted to the bulbis cordis, the first brachial pouch and occasionally the aorta. Over the next few days the virus spreads to multiple tissues, in addition to becoming more widespread and pronounced within the initially infected tissues. A potential role for the binucleated cells of the allantochorion in the spread of the virus from the fetal to the maternal tissues was also found. These cells expressed high levels of viral antigen just prior to and during the time period in which virus antigen became detectable in the epithelial cells of the uterine glands, in endothelial cells of uterine vessels and in scattered macrophage-like cells in the uterine stroma. Most likely this relatively late virus transfer is inconsequential for the mother, since it occurs at a time when a maternal virus-specific antibody response is becoming measurable. This is in contrast to the fetus, where the infection will have established itself widely prior to the development of lymphoid tissues and a functional immune response, thus setting the scenario for development of specific tolerance to the persisting virus.

Production of interferons and beta-chemokines by placental trophoblasts of HIV-1-infected women

OBJECTIVE

The mechanism whereby the placental cells of a human immunodeficiency virus (HIV)-1-infected mother protect the fetus from HIV-1 infection is unclear. Interferons (IFNs) inhibit the replication of viruses by acting at various stages of the life cycle and may play a role in protecting against vertical transmission of HIV-1. In addition the beta-chemokines RANTES (regulated on activation T cell expressed and secreted), macrophage inflammatory protein-1-alpha (MIP-1alpha), and MIP-1beta can block HIV-1 entry into cells by preventing the binding of the macrophage-trophic HIV-1 strains to the coreceptor CCR5. In this study the production of IFNs and beta-chemokines by placental trophoblasts of HIV-1-infected women who were HIV-1 non-transmitters was examined.

METHODS

Placental trophoblastic cells were isolated from 29 HIV-1-infected and 10 control subjects. Supernatants of trophoblast cultures were tested for the production of IFNs and beta-chemokines by enzyme linked immunosorbent assay (ELISA). Additionally, HIV-1-gag and IFN-beta transcripts were determined by a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) assay.

RESULTS

All placental trophoblasts of HIV-1-infected women contained HIV-1-gag transcripts. There were no statistical differences in the median constitutive levels of IFN-alpha and IFN-gamma produced by trophoblasts of HIV-1 infected and control subjects. In contrast, trophoblasts of HIV-1-infected women constitutively produced significantly higher levels of IFN-beta protein than trophoblasts of control subjects. Furthermore, the median levels of beta-chemokines produced by trophoblasts of HIV-infected and control women were similar.

CONCLUSIONS

Since there was no correlation between the placental HIV load and the production of interferons or beta-chemokines, the role of trophoblast-derived IFNs and beta-chemokines in protecting the fetus from infection with HIV-1 is not clear.