淋巴細胞活化蛋白3屬于免疫球蛋白超家族，包含4個胞外免疫球蛋白樣結構域。lag3基因包含8個外顯子。序列數據、外顯子/內含子組織和染色體定位均表明LAG3與CD4有密切關系。
Lymphocyte-activation protein 3 belongs to Ig superfamily and contains 4 extracellular Ig-like domains. The LAG3 gene contains 8 exons. The sequence data, exon/intron organization, and chromosomal localization all indicate a close relationship of LAG3 to CD4.