Skewed cytokine responses in Siglec-E KO mice challenged in a GBS intranasal pneumonia model.

<p>Mice were infected intranasally with 5×10⁷ CFU WT GBS and cytokine levels in cell-free BAL fluid or lung homogenates collected 6 h post infection. (A) Bacterial load in lung tissue was calculated by dilution plating for CFU enumeration. (B) Cells from BAL were counted and stained with mAb to F4/80 and Gr-1 to quantitate infiltrating cell populations. IL-1β (C) and IL-6 (D) in the BAL and IL-10 in lung homogenates (E) were examined by ELISA analysis. Data shown are means ± SEM and each circle denotes 1 mouse (n = 8 for WT and n = 7 for mSiglec-E KO mice). The difference between different groups was calculated by Mann-Whitney test.</p

Reduced brain dissemination and enhanced bactericidal responses in Siglec-E deficient mice upon sublethal GBS challenge.

<p>Comparison of bacterial counts (expressed in CFU) recovered from the kidney (A) and brain (B) of WT mice and Siglec-E KO mice 48 h after intravenous challenge with 1×10⁸ CFU of WT GBS. (C) Brain bacterial counts were corrected for blood contamination (brain/blood ratio) using a conservative estimate of the mouse cerebral blood volume (2.5 ml per 100 g tissue). mRNA expression of IL-1β (D) and IL-12 (E) in lung and IL-10 in spleen (F) was examined by quantitative real time RT-PCR analysis. Results pooled the data from two independent experiment with final numbers of <i>n</i> = 14 for each group. Each circle denotes 1 mouse (A–F). Siglec-E KO microglia cells showed greater bactericidal ability (G) and produced higher levels of TNF-α (H) after GBS challenge. Statistical analysis was performed by Mann-Whitney test (A–F), two-way ANOVA with Bonferroni posttest (G) and one-way ANOVA with Tukey's multiple comparison test (H). *<i>P</i><0.05.</p