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Figure 4 | Retrovirology

Figure 4

From: HIV-1 immune activation induces Siglec-1 expression and enhances viral trans-infection in blood and tissue myeloid cells

Figure 4

The plasma of untreated HIV-1-infected individuals stimulates Siglec-1 expression and signals via type I IFN receptor. A. Mean number of Siglec-1 Ab binding sites per cell induced by the plasma of HIV-1-negative individuals and HIV-1-infected individuals before or after successful antiretroviral treatment, respectively. DCs derived from uninfected donors were cultured for 24 h in the presence of plasma and then stained for Siglec-1. Graph shows mean values and SEM of Siglec-1 induction in DCs from two donors that were tested in parallel with the plasmas from five HIV-1-negative individuals and ten HIV-1-infected individuals. B. Relative blockade of Siglec-1 expression by B18R, a soluble recombinant receptor with high affinity for type I IFNs, which inhibits Siglec-1 induction triggered by the plasmas of untreated HIV-1-infected individuals. DCs were cultured for 24 h with the respective plasma in the presence or absence of 2 μg/ml of B18R. Values are normalized to the level of Siglec-1 induction by plasma of mock-treated cells (set at 100%). Mean changes from 100% were assessed with a one sample t-test. Representative histogram also depicts IFNα-treated DCs. C. Mean number of Siglec-1 Ab binding sites per cell induced by the plasma of untreated HIV-1-infected individuals. DCs were cultured for 24 h in the presence of plasma collected from patients displaying the highest levels of Siglec-1 (>5500 Ab binding sites per monocyte), intermediate levels of Siglec-1 (4000–2500 Ab binding sites per monocyte) or the lowest levels of Siglec-1 (<1500 Ab binding sites per monocyte) and then stained for Siglec-1. Graph shows mean values and SEM of Siglec-1 induction in DCs from two donors that were tested in parallel with the plasmas from ten HIV-1-infected individuals. Man Whitney t-test was used to compare the differences between distinct plasmas to induce Siglec-1 expression.

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