Strain specific CD69 expression analysis in homozygous B-hCD69 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice (+/+) and homozygous B-hCD69 mice (H/H) stimulated with anti-CD3ε and anti-CD28 in vitro, and analyzed by flow cytometry with species-specific anti-CD69 antibody. Mouse CD69 was detectable detectable on T cells, B cells and NK cells in wild-type mice. Human CD69 was detectable on T cells, B cells and NK cells in homozygous B-hCD69 mice but not detectable on those cells in wild-type mice.