Description: The 4D11 monoclonal antibody reacts with Ly-49G2 (also known as LGL-1). The Ly-49 family of NK-cell receptors, members of the C-type lectin superfamily, are disulfide-linked type-II transmembrane protein homodimers with extracellular carbohydrate recognition domains, which bind to MHC class I alloantigens. The Ly-49 family members are expressed independently, such that an individual NK or T cell may display more than one class of Ly-49 receptor. Ly-49G2 is an inhibitory receptor expressed on subsets of natural killer (NK) cells, NK-T cells (in all strains tested), and on a population of memory CD8+ T cells (in C57BL/6 mice). The 4D11 antibody has been reported to cross react with the Ly-49AB6, Ly-49ABALB, and Ly-49T129/J inhibitory receptors and Ly-49LCBA/J activatingreceptors. The proportion of NK-T cells expressing Ly-49A and Ly-49G2 is higher in the thymus than in liver, and there is evidence that down-regulation of Ly-49 receptor expression is necessary for normal NK–T-cell development to occur.