CASEIN EXPRESSION IN CYTOTOXIC LYMPHOCYTES-T

A cDNA that expresses a mRNA restricted to cytotoxic T lymphocytes (CTL) and mammary tissue has been isolated and characterized. The deduced amino acid sequence from this cDNA shows extensive homology with the previously reported amino acid sequence for rat α-casein. Indeed, the presence of a six-residue-repeated motif that is specific for rodent α-caseins strongly supports the identification of this cDNA as mouse α-casein. Northern (RNA) blot analysis of many hematopoietic cell types revealed that this gene is restricted to CTL, being expressed in four of six CTL lines examined. Furthermore, CTL that express this gene were also found to express other members of the casein gene family, such as β- and κ-casein. These results suggest that caseins may be important in CTL function, and their potential role in CTL-mediated lysis is discussed.