Ling V, Wu P W, Finnerty H F, Bean K M, Spaulding V, Fouser L A, Leonard J P, Hunter S E, Zollner R, Thomas J L, Miyashiro J S, Jacobs K A, Collins M
Department of Immunology, Genetics Institute, Cambridge, MA 02081, USA.
J Immunol. 2000 Feb 15;164(4):1653-7. doi: 10.4049/jimmunol.164.4.1653.
By the genetic selection of mouse cDNAs encoding secreted proteins, a B7-like cDNA clone termed mouse GL50 (mGL50) was isolated encoding a 322-aa polypeptide identical with B7h. Isolation of the human ortholog of this cDNA (hGL50) revealed a coding sequence of 309 aa residues with 42% sequence identity with mGL50. Northern analysis indicated GL50 to be present in many tissues including lymphoid, embryonic yolk sac, and fetal liver samples. Of the CD28, CTLA4, and ICOS fusion constructs tested, flow cytometric analysis demonstrated only mouse ICOS-IgG binding to mGL50 cell transfectants. Subsequent phenotyping demonstrated high levels of ICOS ligand staining on splenic CD19+ B cells and low levels on CD3+ T cells. These results indicate that GL50 is a specific ligand for the ICOS receptor and suggest that the GL50-ICOS interaction functions in lymphocyte costimulation.
通过对编码分泌蛋白的小鼠cDNA进行基因筛选，分离出一个名为小鼠GL50（mGL50）的类B7 cDNA克隆，其编码一个与B7h相同的322个氨基酸的多肽。该cDNA人类直系同源物（hGL50）的分离揭示了一个309个氨基酸残基的编码序列，与mGL50有42%的序列同一性。Northern分析表明GL50存在于许多组织中，包括淋巴组织、胚胎卵黄囊和胎儿肝脏样本。在所测试的CD28、CTLA4和ICOS融合构建体中，流式细胞术分析表明只有小鼠ICOS-IgG与mGL50细胞转染体结合。随后的表型分析显示，脾脏CD19+B细胞上ICOS配体染色水平高，而CD3+T细胞上水平低。这些结果表明GL50是ICOS受体的特异性配体，并提示GL50-ICOS相互作用在淋巴细胞共刺激中起作用。
