Free Access

Figure 4.


Neutrophil recruitment across the alveolar epithelium is IL1β dependent. Mammary glands of lactating IL1R −/− mice were infused with 10 μg LPS. H&E staining of formalin-fixed mammary tissues 24 h after LPS inoculation (A−C). Recruited neutrophils (arrows) are trapped in congested capillaries and interstitium unable to transverse the mammary epithelium (A−C). This is better seen in B which is an enlargement of the inset area in A and also in C. Increased neutrophil recruitment to the mammary gland was indicated by the MPO assay (D). Significantly higher relative (LPS to PBS-challenged gland) MPO activity was observed in mammary glands of IL1R −/− mice compared with C57BL/6 mice. Adoptive transfer of 106 wt neutrophils restored normal neutrophil recruitment into the alveolar spaces (E and F) which is also reflected by similar relative MPO activity (D). Data are mean and S.E., n ≥ 6/group and p values represent comparison between groups using the Student t-test. Scale bars 200 μm (A), 50 μm (B and C). (A color version of this figure is available at

Download original image