Model Description: A 2A-CreERT2-WPRE-pA coexpression cassette is inserted befor the stop codon of mouse Cd2 gene via homologous recombination to establish a tamoxifen inducible Cd2-CreERT2 tool stain. This strain can be used to knockout target gene in T cells and B cells after tamoxifen treatment when crossed with mice which carry loxp sites flanking target gene.