Disease relevance of Ly9

• A molecule with properties of T100 was also detected on lymph node cells and on the AKTB-1 lymphoma [1].
• Additionally, Ly9-/- mice differ from SAP-/- mice in that they foster normal development of NKT cells and mount appropriate T and B cell responses to lymphocytic choriomeningitis virus [2].

High impact information on Ly9

• Human Ly-9 expression was restricted to T and B lymphocytes and thymocytes, with the highest levels of expression on CD4(+)CD8(-) and CD4(-)CD8(+) thymocytes [3].
• Molecular characterization and expression of a novel human leukocyte cell-surface marker homologous to mouse Ly-9 [3].
• Northern blot analysis revealed that the human Ly-9 messenger RNA (2.6 kb) is expressed predominantly in lymph node, spleen, thymus, and peripheral blood leukocytes [3].
• Monocytes, granulocytes, platelets, and red blood cells were uniformly negative for Ly-9 [3].
• In contrast to SLAM-/- and SAP-/- mice, T cells from Ly9-/- mice proliferate poorly and produce little IL-2 after suboptimal stimulation with anti-CD3 in vitro [2].

Biological context of Ly9

• In the BXH strains the percentage of genetic variation accounted for by Ly-9 segregation was reduced to 46%, while 54% was accounted for by other genetic factors [4].
• A mouse monoclonal cell line (20-1.5) was produced by the cell fusion method and the antibody secreted by this line defined the Ly-9.2 specificity--the reciprocal specificity to that previously identified as the Lgp 100 or the T100 molecule [5].
• Studies of five recombinant inbred strains and (C57BL/6 X M. spretus) F1 X C57BL/6 backcross mice demonstrated that these RFLPs were allelic and that Spna-1 is closely linked to Ly-9 and Ly-17 on the distal region of chromosome 1 [6].
• Here, we report the isolation and characterization of the Ly9 gene, which encompasses at least 19 kb and contains ten separated exons, with sizes ranging from 54 to 355 bp [7].
• 1. Inheritance and expression of T100 suggest that it is determined by an allele at a single locus, and testing of CXB recombinant inbred strains and B6.C minor histocompatibility congenic strains suggest that this locus is linked to H-25 [1].

Anatomical context of Ly9

• A monoclonal antibody detecting the Ly-9.2 (Lgp 100) cell-membrane alloantigen [5].
• CD229 (Ly9) lymphocyte cell surface receptor interacts homophilically through its N-terminal domain and relocalizes to the immunological synapse [8].
• The Ly9 glycoprotein is a member of the immunoglobulin (Ig) superfamily, which is expressed on the cell surface of B and T lymphocytes [7].
• Ly 9 is expressed on all thymocytes, peripheral lymphocytes, and on a subpopulation of cells in the bone marrow [9].
• Normal mouse spleen cells cultured for 4 days in IL-2-containing lymphokine preparations characteristically killed both NK-sensitive (YAC-1) and NK-resistant (EL4, P815) target cells, and mediated significant lysis of both cultured and freshly isolated trophoblast cells (35 to 55%, E/T 100/1) [10].

Associations of Ly9 with chemical compounds

• More recently, the in vitro effect of roxithromycin against a panel of isolates from AIDS patients has been assessed and it was found that some (but not all) of the inhibitory concentrations, by the T-100 method of Inderlied, are within achievable serum levels [11].

Other interactions of Ly9

• However, in the BXD strains the linkage between Sap and Ly-9 appears to be quite close [4].
• The sequence data also support the view that Ly-9 belongs to the subgroup of the Ig superfamily that includes Bcm-1, CD2, and LFA-3 [12].
• Analysis of RNA showed that Ly-9 expression is lymphocyte specific, as determined by the presence of a single hybridizing 2.4-kb species found only in lymphoid cells [12].
• The inbred stain distribution, trypsin sensitivity on intact cells, and apparent m.w. of T100 suggest that it is different from Lyt-2 [1].
• The B cell alloantigen Ly-17.1 is controlled by a gene closely linked to Ly-20 and Ly-9 on chromosome 1 [13].

Analytical, diagnostic and therapeutic context of Ly9

• Antiserum absorption experiments, two-stage cytotoxicity assays, and results of immunoprecipitations performed after prebinding antibody to radiolabeled thymocytes suggest that some T100 is accessible to antibody on the intact cell surface [1].
• A cell surface glycoprotein (designated T100) of apparent m.w. 100,000 by SDS-PAGE under reducing and nonreducing conditions was precipitated from NP-40 extracts of surface radiolabeled thymocytes from a variety of inbred strains of mice by the standard noncongenic Lyt-2.1-typing serum [1].
• A new lymphocyte cell surface alloantigen, provisionally designated Ly 9, is detected by flow microfluorometry(FMF), as an extra specificity in sera from anti-Lyt immunizations [9].
• Quantitative measurement of Ly 9 immunofluorescence by FMF on heterozygote cells shows that Ly 9 antigen expression is co-dominant and reduced in levels relative to parental homozygote cells [9].

References