title: Suppression of alloimmune cytotoxic T lymphocyte (CTL) generation by depletion of NK cells and restoration by interferon and/or interleukin 2.
abstract: By using rabbit antiserum to a glycolipid, ganglio-n-tetraosylceramide (ASGM1), the accessory effect of natural killer (NK) cells on the generation of alloimmune CTL in mice was investigated. When normal C3H/He mice were immunized with C57BL/6 or BALB/c spleen cells, they generated alloimmune CTL with a surface marker phenotype of Thy-1+ Lyt-1-2+ ASGM1-, preceded by early augmentation of cytotoxic activity of NK cells with a Thy-1-Lyt-1-2-ASGM1+ phenotype. Administration of anti-ASGM1 (10 microliters) in mice resulted in a complete depletion of NK activity and ASGM1+ cells in the spleen even 1 day after injection, but no changes in the proportions of T (Thy-1+) cells and their Lyt-1 and Lyt-2 subsets as revealed by an immunofluorescence analyzer (FACS) and phagocytic cells. When these anti-ASGM1-treated mice were immunized with allogeneic cells, they showed neither augmented NK activity nor generation of alloimmune CTL, and spleen cells isolated from these anti-ASGM1-treated mice produced no CTL response to alloimmunization in vitro. Normal spleen cells treated with the antiserum and complement in vitro also showed a complete NK depletion without any deterioration of T cells and their Lyt-1 and Lyt-2 subsets, and when stimulated with allogeneic cells they generated no CTL. Spleen NK (ASGM1+) cells were purified by Percoll-gradient centrifugations followed by complement-dependent killing of T cells with the use of anti-Thy-1 monoclonal antibody, and were further purified by panning methods with anti-ASGM1, giving a preparation consisting of greater than 90% ASGM1+, Ly-5+ cells, and less than 0.5% of Thy-1+, Lyt-1+, and Lyt-2+ cells. These purified ASGM1+ Thy-1- cells alone generated no alloimmune CTL in response to alloantigens, suggesting that ASGM1+ NK cells contained no precursors of alloimmune CTL. When added into NK-depleted spleen cells, they restored the normal alloimmune CTL response of the spleen cells, indicating that ASGM1+ fractions contained cells to provide an accessory function for CTL generation. Lyt-1+ cells purified by panning methods did not restore the CTL response of NK-depleted spleen cells. These results indicate that ASGM1+ NK cells, but not Lyt-1+ helper T cells contaminating ASGM1+ fractions at undetectable levels, are responsible for the accessory function. When these purified ASGM1+ Thy-1- cells were stimulated with allogeneic cells, they produced IL 2 and IFN.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.forename: R
authors.initials: R
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Ebina
authors.forename: K
authors.initials: K
authors.lastname: Kumagai
mesh_terms: D000818:Animals; D003602:Cytotoxicity, Immunologic; D005677:G(M1) Ganglioside; D006028:Glycosphingolipids / Q000276:immunology; D007106:Immune Sera / Q000008:administration & dosage; D007165:Immunosuppression Therapy / Q000379:methods*; D007372:Interferons / Q000096:biosynthesis / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000502:physiology; D007519:Isoantigens / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D010641:Phenotype; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D006028:Glycosphingolipids; D007106:Immune Sera; D007376:Interleukin-2; D007519:Isoantigens; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside; D007372:Interferons