Abstract
Normal mouse lymphoid cells have been shown to become specifically paralyzed after in vitro exposure to high doses of detoxified endotoxin of Escherichia coli 055:B5. The immune status of the treated cells was tested after transfer to secondary irradiated hosts. Paralysis was shown to be initiated by events taking place in vitro, since the amount of antigen retained on the cells after the in vitro exposure was insufficient to induce paralysis in vivo. The induction of paralysis was dependent on the concentration of antigen added to the cells in vitro. Certain variables, such as time of exposure and temperature at exposure, influenced the ease by which the cells could be paralyzed. Cells pretreated with trypsin were not susceptible to induction of paralysis by the above procedure.