Kindlin-3–deficient effector T cells are retained in the circulation at higher numbers than wt T cells. (A) Relative abundance of coinjected CFSE-labeled wt and CMTMR-labeled Kindlin-3–deficient T cells in blood 40 minutes after intracardiac transfer. The indicated numbers of total T cells were determined by FACS of blood samples, as explained in “Materials and methods.” Mean values ± range of 2 mice. A representative of 4 experiments. ***P < .0002. (B) Accumulation of dye-labeled wt or Kindlin-3–deficient T cells in spleens recovered 40 minutes after intracardiac injection determined by FACS analysis. Mean values ± range of 2 mice. A representative of 4 experiments. Average values ± range. ***P < .0004. (C) The numbers of sham and PTx-pretreated T cells (labeled with either CFSE or CMTMR) recovered in blood 40 minutes after intracardiac injection determined as in panel A. n = 2. n.s., not significant. (D) Effect of pretreatment of wt effector T cells with either LFA-1 or α₄-blocking mAb or with a nonblocking mAb (anti-CD45) on the concentration of T cells circulating in blood. Dye-labeled wt T cells were incubated with each of the mAbs, washed, and coinjected at a 1:1 ratio. The blood concentration of each mAb-treated population was determined as in panel A, and the ratios between each indicated groups are depicted. Results are given as mean ± SEM of 5 to 9 experiments. (E) Effects of pretreatment of dye-labeled Kindlin-3–deficient T cells with either LFA-1 or α₄-blocking mAbs on lymphocyte numbers in blood. Results are mean ± SEM of 3 experiments. (F) wt (CFSE-labeled) or Kindlin-3–deficient (CMTMR-labeled) T cells were coinjected at a 1:1 ratio, and their relative accumulation in the lung (left) and liver (right) was enumerated by FACS analysis 40 minutes later n = 3. **P < .002; ***P < .0002.