Cd28^tm1Shr

A PGK-hygro cassette replaced a 3 kb region encompassing portions of exon 2 and exon 3. The deleted region encoded parts of a IgV-like domain and a transmembrane domain. Fluorescence-activated cell sorting (FACS) analysis showed an absence of protein on naive CD4 T cells isolated from the lymph nodes of homozygous mutant mice. Targeting was performed on an embryonic stem cell clone that was heterozygote for a targeted mutation of Ctla4tm1Shr. (J:68642)