Mice Lacking Expression of Secondary Lymphoid Organ Chemokine Have Defects in Lymphocyte Homing and Dendritic Cell Localization

Gunn, Michael D.; Kyuwa, Shigeru; Tam, Carmen; Kakiuchi, Terutaka; Matsuzawa, Akio; Williams, Lewis T.; Nakano, Hideki

Decreased Expression of ELC in plt Mice. ELC is the chemokine most closely related to SLC. ELC and SLC have similar activities; both activate the CCR7 receptor, and their genes are located within 100 kb of each other in the human genome (24, 39, 40) . In contrast to SLC, ELC expression is limited to interdigitating DCs in LNs and spleen (41) . To determine if the decreased accumulation of DCs in plt mice leads to a decrease in the production of ELC, we examined ELC expression in plt mice. By Northern analysis, ELC mRNA levels in the LNs and spleen of plt mice were reduced compared with Ï©/Ï© mice (Fig. 7 E) . By in situ hybridization, ELC expression was reduced in the LNs of plt mice compared with Ï©/Ï© mice (Fig. 7, A and B) . ELC antisense probes hybridized most strongly to the outer LN cortex in a region corresponding to the area in which DCs accumulated in plt mice (compare Fig. 7 B and Fig. 3 B) . In the spleens of plt mice, ELC expression was also reduced (Fig. 7, C and D) . As in LNs, the hybridization signal in plt spleen localized to regions that correspond to the area in which DCs accumulated (compare Fig. 7 D and Fig. 3 D) . Similar to results in Ï©/Ï© mice, no ELC signal was detected in lymphatics or any nonlymphoid tissue of plt mice (data not shown).