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

Finally, we demonstrate that plt mice have a severe immune deficiency. The LD 50 of MHV in plt mice is reduced Ͼ300-fold compared with ϩ/ϩ mice (Fig. 8) . In comparison, the LD 50 of Sendai virus is reduced 10-fold in mice lacking cytotoxic T cell function and 300-fold in nude mice compared with ϩ/ϩ controls (50) . In our view, the most likely cause of this immune deficiency is a defect in the presentation of viral antigen due to the failure of naive T cells and antigen-bearing DCs to enter the T cell zones of plt mice. It is also possible that SLC, like some other chemokines, provides a signal that enhances the antigendependent activation of lymphocytes (51, 52) . A third possibility is that SLC, expressed in the thymus and in lymphatics, has a role in lymphocyte development or in the efferent limb of immune response that has not yet been characterized.