Conclusion
Use of Aldh1l1-Cre/ERT2 should therefore account for recombination in both astrocytes and immune cells in disease models involving peripheral immune cell infiltration into the CNS.
Methods
Two astrocyte-targeted mouse lines were generated with the red fluorescent reporter, tdTomato, by crossing the Cre-recombinase lines, Tg(Aldh1l1-Cre/ERT2)1Khakh and Tg(Gfap-Cre)73.12Mvs, with the reporter line, Gt(ROSA)26Sor. Aldh1l1-Cre/ERT2 was activated with 5 days of intraperitoneal tamoxifen, whereas Gfap-Cre was constitutively active. EAE was induced 2 weeks after tamoxifen, and then spleens and spinal cords were harvested and processed for flow cytometry at various time points after disease onset in EAE versus healthy controls.
Results
In EAE, Aldh1l1-Cre/ERT2, but not Gfap-Cre, induced multiple tdTomato+ immune cell subpopulations in the spleen and spinal cord, including macrophages, monocytes, neutrophils, eosinophils, B cells, CD4+, and CD8+ T cells.