Fig. 6.

12-lipoxygenase activity is required for pulmonary inflammation during S. pneumoniae infection of mice. Untreated [“+TIGR4”; panel A(ii)] or CDC-treated [“+CDC, +TIGR4”; panel A(iii)] wild type (“WT”) C57BL/6 mice, or Alox15^−/− [panel A(iv)] mice were inoculated intratracheally with TIGR4, or with PBS alone [panel A(i)], as described in Materials and Methods. Mice were sacrificed, and hematoxylin and eosin stained lung sections (at 20× magnification) were examined by light microscopy. Inset: lung sections at 40× magnification; arrowheads denote PMNs. Figures are representative of two independent experiments. Bronchoalveolar lavage fluid (BALF) was isolated and cytospin preparations were prepared. PMNs were counted from Wright-Giemsa stained preparations by observation at 100×. Average number of PMNs per 5 fields of observation is noted in the corresponding histology figures. For flow cytometry, BALF and lungs from infected WT (with or without CDC treatment) or Alox15^−/− mice were collected. Cells present in the digested lungs and BALF were stained with relevant MAbs and the fluorescence intensities of the stained cells were determined by flow cytometry. Collected data were analyzed to determine the numbers of PMNs, macrophages (Mɸ), dendritic cells or T cells in the lungs (B, top) and in the BALF (B, bottom).