FIG. 3.

In vivo cytolytic activity against FrCas^E-infected splenocytes in infected/treated/nondepleted mice. Splenocytes were prepared either from control noninfected mice or from infected mice (see Materials and Methods) and labeled with 1× or 10× CFSE, respectively. They were then mixed in an approximately 1:1 ratio and administered intravenously to either naive (control) or infected/treated/nondepleted mice (2 months old). Sixteen hours later, splenocytes from grafted mice were purified and analyzed by flow cytometry to determine the intensity of CFSE labeling. A reduction of 10× CFSE-labeled cells in infected/treated/nondepleted mice, but not in control mice, is indicative of cytotoxic activity against infected splenocytes. (A) Flow cytometry analysis. Two representative control and two representative infected/treated/nondepleted mice are presented. Splenocytes were analyzed for CFSE fluorescence as described in Materials and Methods. (B) Statistical representation of the data. Each histogram corresponds to an analysis of 12 mice. The cytotoxic activity against infected splenocytes was calculated from the ratio of CFSE^high/CFSE^low cells 16 h after adoptive transfer corrected by the CFSE^high/CFSE^low ratio assayed before grafting cells into recipient mice. Error bars correspond to the standard deviation.