Figure 2. In vitro culture of B. mori hemocyte-progenitor cells.

A: dispersed HPO cells viewed under a differential interference microscope. B: these cells were seeded into 24-well multiplates at a density of 2×105 cells/500 µl medium/well. C–H: the cells were cultured in medium containing 3% larval plasma (C, E, G) or plasma-free medium (D, F, H). Cells were viewed at 24 h (C, D), 72 h (E, F), and 168 h (G, H). Yellow arrowheads: spindle-shaped plasmatocytes. Black arrowheads: a collapsed oenocytoid and a spherulocyte, which had probably contaminated the HPO. Red arrowheads: oenocytoids appearing during culture. Blue arrowheads: shrunken cells (inset of panel F is a magnified image of a shrunken cell). All figures are at the same magnification (bar  = 50 µm).