Interleukin-10 production during pregnancy reduces HIV-1 replicaction in cultures of maternal lymphocytes

PURPOSE: to evaluate T cell proliferation and cytokine production in HIV-1-infected pregnant women and their impact on in vitro virus replication. METHODS: peripheral blood from 12 HIV-1-infected pregnant women and from their neonates was collected. As control, 10 samples from non-infected pregnants were also colleted. The CD4+ and CD8+ T cell counts were assayed by flow cytometry. Peripheral blood mononuclear cells (PBMC) and plasma were obtained by centrifugation with and without Ficoll-Hypaque gradient, respectively. The freshly purified PBMC were kept in cultures for seven days with PHA plus r-IL-2, and the lymphoproliferative response was assayed by Trypan blue dye exclusion. In some experiments we added anti-IL-10 monoclonal antibody. The plasma samples and supernatants from cell cultures were stored to determine both peripheral cytokine levels, by ELISA sandwich, and viral load, by RT-PCR. RESULTS: the results showed that the lymphoproliferative response was smaller in cultures obtained from HIV-1-infected women than in control cultures [4.2±0.37 vs 2.4±0.56 (x 10(6) cell/mL), p<0.005]. In both control and infected pregnant women who had low plasma viral load, the level of IL-10 was higher than in those with high viral replication (9.790±3.224 vs 1.256±350 pg/mL, p=0.002). The elevated TNF-alpha production detected in serum (7.200±2.440 pg/mL) and supernatants (21.350±15.230 pg/mL) was associated with higher plasma viral loads and vertical infection. The IL-10 blockade by anti-IL-10 antibodies augmented viral replication in the cell cultures. CONCLUSION: these results indicate that IL-10 production exerts a negative influence on virus replication, diminishing the probability of intrauterine HIV-1 infection.

Aqured immunodeficency; Cytokines; HIV-1; Th1-cells; t Lymphocytes

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