FIG. 7.

In vivo FcγR-dependent cytolytic activities of the 667 MAb, the 667 F(ab′)₂ fragment, and the 672 MAb. The assessment of FcγR-dependent cytolytic activities of the 667 MAb, the 667 F(ab′)₂ fragment, and the 672 MAb is described in Materials and Methods. Briefly, noninfected and FrCas^E-infected splenocytes differentially labeled with high and low concentrations of the vital dye CSFE were administered intravenously to naive mice or to mice formerly treated with the anti-FcγRII and anti-FcγRIII 2.4G2 MAb. At the same time, the animals received either the 667 MAb, the 667 F(ab′)₂ fragment, or the 672 MAb. Flow cytometry assay of CFSE^low/CFSE^high ratios from cells recovered from spleens 5 h later to allow the comparison of the in vivo cytolytic activity of the anti-FrCas^E MAbs and F(ab′₂) in the presence or in the absence of FcγR-blocking MAb. Two mice per group were used in three independent experiments. Error bars indicate standard deviations.