Dithiothreitol-dependent antilisterial activity of lysates from normal macrophages exposed in vitro to culture fluids from spleen cells of BCG-immunized mice.

The effect of culture fluids from mouse lymphocytes on the antilisterial activity of normal macrophages in vitro was determined. Titers of lysates of macrophages incubated with or without culture fluids from lymphocytes from control mice had titers of 10 to 270 with or without a reducing agent, dithiothreitol. Lysates of macrophages after incubation with culture fluids of spleen lymphocytes from BCG-immunized mice had antilisterial titers with and without dithiothreitol of 197,000 and 810, respectively. This may indicate a dithiothreitol-dependent antilisterial system inherent in activated macrophages of cell-mediated immunity. Lysates of incubated spleen cells and their culture fluids also had slight antilisterial activity.