Blood B cells respond better to chemokines and express lower levels of RGS proteins than do LN B cells. (A) Chemotaxis assays. LN and blood B cells were tested in standard chemotaxis assays immediately after isolation. Specific migration to CXCL12, CCL19, and CXCL13 are shown (5-μm pore size). Results are from analysis of negatively selected B cells prepared from pooled LN cells prepared from the inguinal LNs of 6 mice and blood from 15 mice. (B) Comparison of chemokine receptors. Flow cytometry analysis of different chemokine receptors and CD62L on blood and lymph node B cells. Results are from analysis of FACS sorted B cells prepared from pooled LN cells prepared from the inguinal LNs of 6 mice and blood from 15 mice. (C) Comparison of CXCL13 induced changes in [Ca²⁺]_i. CXCL13 induced changes in [Ca²⁺]_i were monitored over 4 minutes after exposing purified blood or inguinal LN B cells to the indicated concentrations. The data shown as fluorescent counts and the y-axis labeled as Lm1. Each experimental value is the mean of 3 determinations of peak values. The same cells as used in panel B. (D) Rgs protein mRNA expression in blood and LN B cells. FACS sorted CD19 and B220 double-positive cells from blood or LN were used to prepare mRNA for quantitative RT-PCR. Each value was normalized to the sample's actin levels and shown as a ratio between the LN and blood B cell value.