Figure 2.

Effect of chemokine desensitization on T and B cell interactions with PP-HEVs. (A) T cell or (B) B cell subpopulations of LNCs were enriched by negative selection (see Materials and Methods), labeled, and incubated with 1 μM of indicated chemokine or control medium as in Fig. 1, then injected (mixed 1:1 with internal standard cells), and their behaviors were observed within PP-HEVs. Data collection was as in the legend to Fig. 1 except for B cells (which accumulated faster than T cells; data not shown), for which total flux and rolling fraction were analyzed during a 2-min time period 4–6 min after injection. Data are percentages of mock-treated control, and represent mean results of two to four experimental animals for each combination of subset and treatment (± SD). Control T cell total flux in vessels examined ranged from 14 to 60 cells/min, mean 48 ± 24 SD, and rolling fraction from ∼35 to 93%. Control B cell total flux ranged from 8 to 74 cells/min, mean 32 ± 18 SD, and rolling fraction from 25 to 84%, mean 54 ± 23%. Rolling velocity of T cells (range 23–197 μm/s, mean 94 ± 33 SD, comparable to previous reports [references 2, 41]) was not effected by SLC desensitization (range 24–160 μm/s, mean 99 ± 44 SD). B cell rolling velocities were similar (range 27–120 μm/s, mean 55 ± 25 SD). Inhibition of T cell accumulation by SLC or MIP-3β desensitization is significant compared with control or SDF-1α desensitization by Student's t test (P < 0.01).