The Cdh5-CreERT2 transgene causes conditional Shb gene deletion in hematopoietic cells with consequences for immune cell responses to tumors.

The tamoxifen-responsive conditional Cdh5-CreERT2 is commonly used for endothelial cell specific conditional deletion of loxP-flanked gene sequences. To address the role of endothelial cell Shb gene for B16F10 melanoma immune responses, tamoxifen-injected Cdh5-CreERT2/WT and Cdh5-CreERT2/Shb mice received subcutaneous tumor cell injections. We observed a decrease of tumor myeloid cell Shb mRNA in the tamoxifen treated Cdh5-CreERT2/Shb mice, which was not present when the mice had undergone a preceding bone marrow transplantation using wild type bone marrow.