Interethnic and intraethnic differences in the frequency and activation markers of circulating monocytes.

<p>PBMCs were stained with monoclonal antibodies and subsequently analyzed using FACSCalibur. The samples were categorized as uninfected Dogon (n = 20), infected Dogon (n = 20), uninfected Fulani (n = 13) and infected Fulani (n = 10). An increase of circulating monocytes was observed for both groups although only statistically significant for the Dogon (Figure 2A). There was a decreased expression of HLA-DR (Figure 2B) in classical monocytes for both ethnic groups. The levels of HLA-DR were also suppressed in the inflammatory monocytes although not statistically significant for the Dogon. The expression of CD86 (Figure 2C) was decreased on both monocytic subsets although only statistically significant for the Dogon classical monocytes from both Dogon and Fulani. Although the levels of activation markers seem similarly regulated in both groups the classical monocytes of the Fulani exhibit a pattern of higher activation when undergoing infection than the Dogon when infected. The boxplots illustrate the medians and the 25^th and 75^th quartile and the whiskers represent the 10% and 90% percentiles. Data were analyzed by Mann-Whitney rank sum test. *; p≤0.05. ***; p<0.001.</p

Interethnic and intraethnic differences in the frequency and activation markers of blood DCs.

<p>PBMCs from the study participants were stained with monoclonal antibodies for subsequent flow cytometric analysis using a FACSCalibur. The samples were categorised as uninfected Dogon (n = 20), infected Dogon (n = 20), uninfected Fulani (n = 13) and infected Fulani (n = 10). An increase was observed of BDCA2⁺ and BDCA3⁺ cells in the circulation of infected Dogon whereas the opposite was seen for the Fulani (Figure 1A). The expression of activation marker HLA-DR (Figure 1B) and CD86 (Figure 1C) was lower in BDCA2⁺ and BDCA3⁺ cells of the Dogon when undergoing infection while it was increased in the Fulani. It is known that DCs travel to the lymph nodes upon activation. Therefore, it is possible that the lower numbers seen in the infected Fulani is a consequence of activation. The boxplots illustrate the medians and the 25^th and 75^th quartile and the whiskers represent the 10% and 90% percentiles. Data were analyzed by Mann-Whitney rank sum test. *; p≤0.05. **;p<0.01. ***; p<0.001.</p

Tunable White-Light Emission in Single-Cation-Templated Three-Layered 2D Perovskites (CH₃CH₂NH₃)₄Pb₃Br_{10–<i>x</i>}Cl_<i>x</i>

Two-dimensional (2D) hybrid halide perovskites come as a family (B)₂(A)_<i>n</i>−1Pb_<i>n</i>X_3<i>n</i>+1 (B and A= cations; X= halide). These perovskites are promising semiconductors for solar cells and optoelectronic applications. Among the fascinating properties of these materials is white-light emission, which has been mostly observed in single-layered 2D lead bromide or chloride systems (<i>n</i> = 1), where the broad emission comes from the transient photoexcited states generated by self-trapped excitons (STEs) from structural distortion. Here we report a multilayered 2D perovskite (<i>n</i> = 3) exhibiting a tunable white-light emission. Ethylammonium (EA⁺) can stabilize the 2D perovskite structure in EA₄Pb₃Br_{10–<i>x</i>}Cl_<i>x</i> (<i>x</i> = 0, 2, 4, 6, 8, 9.5, and 10) with EA⁺ being both the A and B cations in this system. Because of the larger size of EA, these materials show a high distortion level in their inorganic structures, with EA₄Pb₃Cl₁₀ having a much larger distortion than that of EA₄Pb₃Br₁₀, which results in broadband white-light emission of EA₄Pb₃Cl₁₀ in contrast to narrow blue emission of EA₄Pb₃Br₁₀. The average lifetime of the series decreases gradually from the Cl end to the Br end, indicating that the larger distortion also prolongs the lifetime (more STE states). The band gap of EA₄Pb₃Br_{10–<i>x</i>}Cl_<i>x</i> ranges from 3.45 eV (<i>x</i> = 10) to 2.75 eV (<i>x</i> = 0), following Vegard’s law. First-principles density functional theory calculations (DFT) show that both EA₄Pb₃Cl₁₀ and EA₄Pb₃Br₁₀ are direct band gap semiconductors. The color rendering index (CRI) of the series improves from 66 (EA₄Pb₃Cl₁₀) to 83 (EA₄Pb₃Br_0.5Cl_9.5), displaying high tunability and versatility of the title compounds

Interethnic and intraethnic differences in the TNF-α/IL-10 and IFN-γ/IL-10 ratios upon TLR stimulation of PBMCs.

<p>PBMCs (1 million/ml) were stimulated or not with LPS (100 ng/ml), CpG-A (3 µg/ml) or imiquimod (1 µg/ml). After 16 hours, supernatants were collected, cytokine levels were analyzed and the TNF-α/IL-10 (Figure 4A) and IFN-γ/IL-10 (Figure 4B) ratios were calculated. The samples from 77 children were categorized as uninfected Dogon (n = 20), infected Dogon (n = 20), uninfected Fulani (n = 23) and infected Fulani (n = 14). The TNF-α/IL-10 ratio (Figure 4A) was significantly lower in the infected Dogon as compared to their uninfected peers when stimulated with CpG or imiquimod. This resulted in significantly higher TNF-α/IL-10 ratio of infected Fulani as compared to the infected Dogon. Due to the severe suppression of IFN-γ the IFN-γ/IL-10 ratios (Figure 4B) were severely suppressed in the LPS and CpG stimulated cells of the Dogon and therefore higher in the infected Fulani than in the infected Dogon. The boxplots illustrate the medians and the 25^th and 75^th quartile and the whiskers represent the 10% and 90% percentiles. Data were analyzed using Mann-Whitney rank sum test. *; p≤0.05. **; p<0.01. ***; p<0.001.</p

TLR-induced cytokine responses in PBMCs from Dogon and Fulani children with or without <i>P. falciparum</i> infection.

<p>PBMCs (1 million/ml) were stimulated or not with LPS (100 ng/ml), CpG-A (3 µg/ml) or imiquimod (1 µg/ml). After 16 hours, supernatants were collected and analysed for the presence of cytokines. The samples were categorized as uninfected Dogon (n = 20), infected Dogon (n = 20), uninfected Fulani (n = 14) and infected Fulani (n = 23). The levels of IL-1β, IL-6, IL-10, TNF-α and INF-γ were severely supressed in the infected Dogon as compared to their uninfected peers when the cells had been stimulated with either LPS or CpGA. As a result, the levels of the infected Fulani were higher than infected Dogon for all cytokines except for IFN-α when stimulated with LPS and except for IL-1β and IL-10 when stimulated with CpG. Similarly, when stimulated with imiquimod cells of the infected Fulani secreted higher levels of IL-6, IFN-α, TNF-α and INF-γ than the infected Dogon due to the suppressed secretion of Dogon when undergoing infection. Data presented as box plots illustrate the medians and the 25^th and 75^th quartile and the whiskers represent the 10% and 90% percentiles. Data were analyzed using Mann-Whitney rank sum test. *; p≤0.05. **; p<0.01. ***; p<0.001.</p

Kinetics of vaccine-specific IgG levels in children during the dry season and after acute malaria.

<p><b>(A)</b> The study was designed to take advantage of the sharply demarcated and intense 6-month malaria season (July—December) and 6-month dry season (January—June; negligible malaria transmission) in Mali. Shown is the number of febrile malaria episodes per day over two years at the study site in a cohort of 695 children and adults. <b>(B)</b> IgG levels specific for routine vaccines administered under one year of age (tetanus, measles and Hepatitis B) were measured in plasma collected from 54 children at four time points (vertical arrows): before and after the 6-month dry season, 10 days after the first acute malaria episode of the ensuing malaria season, and after the second dry season. Shown for each subject are IgG titers specific for <b>(C)</b> tetanus, <b>(D)</b> measles and <b>(E)</b> hepatitis B vaccines at the time points indicated in <b>(B)</b>. The x-axis indicates the age at which the respective time points occurred for each subject. In red are subjects who experienced an accelerated decline in vaccine-specific IgG titers following acute malaria (between 2^nd and 3^rd time points) relative to each child’s own rate of change during the preceding dry season (between 1^st and 2^nd time points). The percentage of subjects for whom malaria was associated with an accelerated decline in IgG is shown in red text for each vaccine. A linear mixed effects model that included three time points over 18 months (before and after the first dry season, and after the second dry season) was used to estimate average IgG half-lives for all subjects (black dashed line) and separately for children aged ≤3 years (green dotted line) and >3 years of age (blue dash-dot line).</p

Rate of change of vaccine-specific IgG levels during the dry season versus during malaria exposure and percentage of children with protective IgG levels.

<p>¹Results based on the last time point of the study period.</p><p>²Standard error.</p><p>³p value for the difference in slopes between the dry season and period of malaria exposure was obtained by fitting a linear mixed effects model.</p><p>⁴Indicates that the slope is significantly different than zero.</p><p>Rate of change of vaccine-specific IgG levels during the dry season versus during malaria exposure and percentage of children with protective IgG levels.</p

Malaria-induced interferon-γ drives the expansion of Tbet^hi atypical memory B cells

<div><p>Many chronic infections, including malaria and HIV, are associated with a large expansion of CD21⁻CD27⁻ ‘atypical’ memory B cells (MBCs) that exhibit reduced B cell receptor (BCR) signaling and effector functions. Little is known about the conditions or transcriptional regulators driving atypical MBC differentiation. Here we show that atypical MBCs in malaria-exposed individuals highly express the transcription factor T-bet, and that T-bet expression correlates inversely with BCR signaling and skews toward IgG3 class switching. Moreover, a longitudinal analysis of a subset of children suggested a correlation between the incidence of febrile malaria and the expansion of T-bet^hi B cells. The Th1-cytokine containing supernatants of malaria-stimulated PBMCs plus BCR cross linking induced T-bet expression in naïve B cells that was abrogated by neutralizing IFN-γ or blocking the IFN-γ receptor on B cells. Accordingly, recombinant IFN-γ plus BCR cross-linking drove T-bet expression in peripheral and tonsillar B cells. Consistent with this, Th1-polarized Tfh (Tfh-1) cells more efficiently induced T-bet expression in naïve B cells. These data provide new insight into the mechanisms underlying atypical MBC differentiation.</p></div

Atypical MBCs and immunoglobulin class switching.

<p>Class-switching of atypical MBCs was assessed by measuring cell surface expression of IgG by flow cytometry in the peripheral blood of <i>Pf</i>-naive U.S. adults (n = 10), <i>Pf</i>-infected Peruvian adults (n = 18) and <i>Pf</i>-infected Malian adults (n = 12). Box-and-whisker plots represent the smallest and largest values (whiskers), the lower and upper quartiles (top and bottom of box), and the median (horizontal line across box). The Mann-Whitney test was used to compare continuous variables between groups.</p

Supernatants of PBMCs stimulated with <i>P</i>. <i>falciparum</i>-infected RBCs plus BCR cross-linking drive T-bet expression in B cells.

<p>(<b>A-C</b>) PBMCs of healthy U.S. adults (n = 5) were stimulated in vitro with <i>P</i>. <i>falciparum</i>-infected red blood cell (iRBC) lysate or uninfected red blood cell (uRBC) lysate for 3 days. The resulting supernatants or the iRBC lysate alone were transferred to PBMCs from the same U.S. adults (n = 5) in the presence of media alone, anti-IgM, anti-CD40, or both, followed by staining for T-bet, CD10, CD19 and IgD. (<b>A</b>) Fold change in T-bet MFI in stimulated naïve B cells relative to unstimulated naïve B cells (left, representative histograms). Fold change in percentage of T-bet intermediate (T-bet^int) and T-bet high (T-bet^hi) (<b>B</b>) naïve B cells and (<b>C</b>) memory B cells after BCR cross-linking with anti-IgM/G/A in the presence of media alone, uRBC/PBMC supernatant or iRBC/PBMC supernatant, relative to unstimulated cells. Horizontal bars and whiskers represent means or median and SE. p values were determined by paired Student’s <i>t</i> test with Bonferroni adjustments where appropriate. ****<i>P</i><0.0001, ***<i>P</i><0.001, **<i>P</i><0.01, *<i>P</i><0.05, ns = not significant.</p