title: Surface Ly-5 glycoprotein in murine natural killer (NK) cell development, target binding and cytotoxicity.
abstract: The role of surface Ly-5 glycoprotein expression in the binding and lysis of susceptible tumor targets by natural killer cells was studied using NK cell-enriched splenocytes from 6-8 week old C57BL/6 mice which were reacted with anti-Ly-5 serum in the presence or absence of a source of complement. A conjugate assay was used to demonstrate that abrogation of tumor cell lysis by anti-Ly-5 serum involved the inhibition of NK cell binding to susceptible YAC-1 targets. Additionally, reconstituted membrane vesicles from NK cell-enriched splenocyte populations blocked binding of effector cells to YAC-1 lymphoma targets, a phenomenon which was abrogated by pretreatment of vesicles with anti-Ly-5 serum. Indirect immunofluorescent labeling and cell sorting were used in the physical separation of Ly-5+ and Ly-5- cells to examine the effect of interferon and interleukin preparations on Ly-5 expression and Nk activity. Three hour treatment of sorted Ly-5- cells with murine alpha + beta interferon resulted in conversion of 22% of the cells to an Ly-5+ phenotype, as well as a significant increase in the percent specific lysis of NK-susceptible YAC-1 targets when compared to freshly sorted Ly-5- cells (29.5 +/- 1.9 vs 2.6 +/- 4.0; p less than .001). In vitro proliferation of sorted Ly-5- cells was induced by three week culture in an interferon- and interleukin-containing supernatant from ConA stimulated BALB/c splenocytes (CM), followed by repeat analysis of Ly-5 expression and cytotoxic activity. Cell sorter purified Ly-5- cells cultured in CM acquired substantial surface Ly-5 with concomitant high levels of cytotoxic activity that remained partially susceptible to inhibition by anti-Ly-5 serum. The data presented suggest that surface Ly-5 glycoprotein expression is important for binding of freshly isolated NK cells to YAC-1 targets. In addition, Ly-5- precursors of NK cells are present in murine splenic tissues and can be induced by CM to become highly active effector cells with increased surface Ly-5 expression. The persistent susceptibility of a subset of these cells to inhibition of cytotoxic activity by anti-Ly-5 serum provides additional evidence of an important role for the Ly-5 glycoprotein in the natural killer cell cytolytic mechanism against certain targets.
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001665:Binding Sites; D003602:Cytotoxicity, Immunologic; D066298:In Vitro Techniques; D007370:Interferon Type I / Q000494:pharmacology; D007518:Isoantibodies / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D011971:Receptors, Immunologic; D013154:Spleen / Q000276:immunology
chemical_list: D000950:Antigens, Ly; D000954:Antigens, Surface; D007370:Interferon Type I; D007518:Isoantibodies; D011971:Receptors, Immunologic