Ly-49 receptor expression and functional analysis in multiple mouse strains

We present data on the strain distribu- tion and functional characteristics of the Ly-49 receptors A, C/I, D, and G2 on DX5 1 natural killer (NK) cells. We have examined tyrosine phosphory- lation of the Ly-49 molecules, regulation of NK cytotoxic functions, and in vivo marrow rejection capability. The flow cytometry results demonstrate a diverse and complex pattern of expression of the Ly-49 receptors in the 11 strains examined. The vast majority of NK cells express Ly-49s, although some NK1.1 1 CD3 1 cells also express these recep- tors. The results of our functional analysis indicate that H-2D d was able to inhibit the function of Ly-49G2 1 NK cells, not only in B6 mice, but also by NK cells derived from several haplotypes. The examination of Ly-49 receptor tyrosine phosphory- lation, which is a biochemical measure of inhibitory function, was consistently observed in the 11 mouse strains examined. In contrast, analysis of Ly-49D function suggests its expression appears to be more restricted and that H-2D d is an activating ligand for this receptor. In addition, the in vivo examination of both inhibitory (Ly-49G2) and activating (Ly- 49D) receptors demonstrated regulatory roles of these class I binding receptors in marrow transplan- tation. J. Leukoc. Biol. 66: 512-520; 1999.