FIGURE 2.

Requirement of integrin βν for phagocytosis but not humoral response after septic infection with S. aureus. A, adult flies of control (w¹¹¹⁸) and integrin βν-deficient (betaInt-nu²) lines were injected with FITC-labeled wild-type S. aureus and analyzed for the level of phagocytosis in vivo. Phase contrast and fluorescence views of the same microscopic fields are shown as vertically aligned panels. Parts of fly abdomen containing clusters of fluorescent materials, indicative of phagocytosis by hemocytes, are shown with squares, and their magnified views are exhibited at the right. The number of flies that gave the fluorescent clusters similar in size to that shown here is indicated in the panels (the denominator is the total number of flies analyzed). Scale bars, 0.5 mm. B, larval hemocytes isolated from the indicated fly lines were subjected to immunocytochemistry with anti-integrin βν or control rat serum. Phase contrast and fluorescence views of the same microscopic fields are shown as vertically aligned panels. Scale bar, 10 μm. C, an assay for phagocytosis in vitro was conducted with fluorescence-labeled wild-type S. aureus, latex beads, E. coli, or B. subtilis as targets and larval hemocytes prepared from the indicated fly lines as phagocytes. D, adult flies of the indicated lines were injected with wild-type S. aureus (bacteria) or solvent alone (PBS). After 18 h, flies were subjected to quantitative RT-PCR for the amount of drosomycin mRNA, which is shown relative to that in the control experiment (w¹¹¹⁸ injected with PBS) as 1.