CD16- CD56+ Natural Killer Cells After Bone
From www.bloodjournal.org by guest on July 6, 2016. For personal use only. CD16- CD56+ Natural Killer Cells After Bone Marrow Transplantation By Roland Jacobs, Matthias Stoll, Gertrud Stratmann, Regine Leo, Hartmut Link, and Reinhold E. Schmidt Natural killer (NK) cells are phenotypically defined as lymphocytes expressingthe antigens CD56 and mostly CD16 (FcyRIII), but lacking CD3. A small CD3- CD16- CD56+ NK cell subset has been described in normal individuals representing less than 2% of peripheral blood lymphocytes. We analyzed here 70 patients for their reconstitution of the immune system during follow-up after autologous or allogeneic bone marrow transplantation. In 35% of these patients, two different NK cell subsets, namely CD56+dimand CD56+brightcells, were observed. The mean duration of these two subsets after transplant was 4 months. Sixty-five percent of the patients exhibited an increased number of NK cells, but only the typical CD16+ CD56+dimpopulation.The CD56+brigMsubpopulation represented a particular CD3- CD16- NK subset, with posttransplantfrequencies up to 70% of all NK cells and 40% of peripheral blood lymphocytes, respectively.In contrast to normal CD56+dimNK cells, CD56+bnghtcells coexpressed the activation antigens p75 p-chain of interleukin-2 receptor (IL-2R). CDSR, and CD26, but were negativefor CD16. NK and antibody-dependent cellular cytotoxicityactivityof CD56+bngM cells was low compared with CD56+dimNK cells. But using IL-2 and interferon y, their cytotoxicity could be enhanced even more than in CD56+dimlymphocytes. These different subsets may reflect distinct activation or differentiation steps of NK cells during reconstitution of the immune system. Their differential response to IL-2 may be of functional importance for posttransplantcytokine therapy. o 1992 by The American Society of Hematology. N Balanced Salt Solution and PB mononuclear cells (PBMC) were separated by centrifugation over a ficoll-hypaque gradient (Seromed, Berlin, Germany). Nonadherent cells were obtained from PBMC by 1hour of adherence on plastic culture dishes at 37°C. For some experiments, these cells were sorted using a FACStarPIUs (Becton Dickinson, Heidelberg, Germany). Cells were stained with CD56 (Leu19 PE) MoAbs for 30 minutes at 4"C, washed three times, and sorted corresponding to the density of CD56 surface expression into CD56+dimand CD56+brightcells at a rate of 3,000 cellsls. When the cell counts were too low for FACS sorting, lymphocytes were depleted of T cells by using CD3 MoAb (OKT3) and magnetic goat antimouse IgG beads (Dynabeads M450; Dynal, Oslo, Norway). Negative cells were depleted of either CD56+bright cells using p75 MoAb (Tu27) or CD56+dimcells using CD16 MoAb (B73.1) and Dynabeads. For depletion, cells were incubated with the primaly MoAb for 30 minutes at 4°C. After three washes, Dynabeads were added at a bead:cell ratio of 1O:l. After 30 minutes of incubation on ice, cells were separated using a magnetic particle concentrator (Dynal) for 5 minutes. All purification steps were performed in RPMI 1640 containing 1% human AB serum. MoAbs. The MoAbs used have been extensively characterized? CD2 (Leu2), CD3 (Leu4), CD8 (LeuSb), CD16 (Leullb), CD20 (Leul6), CD56 (Leu19 PE), and CD25 were purchased from Becton Dickinson. CD3 (OKT3), CD4 (OKT4), and CD8 (OKT8) were from Ortho (Neckargemund, Germany). CD2R (T11.3), CD26, and CD56 (NKH-1A) were generously provided by Drs S.F. Schlossman, E. Reinherz, and J. Ritz (Dana Farber Cancer Institute, Boston, MA). CD16 (B73.1) was a generous gift from B. Perussia (Thomas Jefferson University, Philadelphia, PA). The ATURAL KILLER (NK) cells are defined functionally by their ability to spontaneously lyse tumor cells or virally infected cells without major histocompatibility complex (MHC) restriction.' From various studies they are assumed to play an important role after bone marrow transplantation (BMT) by mediating the graft-versusleukemia e f f e ~ t . Phenotypically, ~-~ NK cells are characterized by expression of the CD56 (NKH-1) antigen.6,7This antigen represents the 140-Kd isoform of the neural cell adhesion molecule (N-CAM) molecule, and is in peripheral blood (PB), largely specific for NK But it also can be detected on non-MHC-restricted cytotoxic lymphocytes and in vitro-activated T-cell clones. In addition, the majority of NK cells can be identified by monoclonal antibodies (MoAbs) against the CD16 (FcyRIII) antigen functionally responsible for the ADCC exerted by NK cells.' By definition all NK cells are CD3- T-cell receptor (TCR) n e g a t i ~ e . ~ The lineage and ontogeny of NK cells is still a controversial issue. There are characteristics of T-cell lineage, such as the incomplete message of the P-chain of the TCR, CD2 expression, and use of the (-chain of the CD3 On the other hand, antigens of the myeloid lineage, such as CD16 or CDllb, are expre~sed.~,'~ Recently, a small subset of PB lymphocytes (PBL) ( < 2%) has been described in normal individuals expressing CD56 brightly that are also CD3- and CD16-.11.12 CD16- NK clones could be isolated from human thymus.I4 The detection of this subset has led to new speculations regarding the in vivo differentiation of NK cells.15 In the present study, the reconstitution of NK cells in patients after BMT was analyzed. In contrast to normal NK cells, the presence of two distinct NK cell subpopulations, namely, CD16+ CD56+dimand CD16- CD56+bribtcells, could be detected. In addition, the different phenotypic and functional characteristics of these NK cell subsets are described. MATERIALS AND METHODS Patients. The characteristics of the patients examined are summarized in Table 1. All patients were analyzed for the phenotypic pattern of PBL weekly post-BMT. Cell preparation. Heparinized blood samples were obtained from the patients as soon as lymphocytes were identified in the blood. The blood was diluted with an equal volume of Hank's Blood, Vol79, No 12 (June 15). 1992: pp 3239-3244 From the Abt. fur Klinische Immunologie und Transfusionsmedizin, Interdisziplinare Einheit fur Knochenmarktransplantation, Zentrum Innere Medizin und Dermatologie, Medizinische Hochschule Hannover, Hannover, Germany. Submitted October 2, 1991; accepted Februaty 12, 1992. Supported by the Deutsche Forschungsgemeinschaft Schm 59612-2 and SFB 265. Address reprint requests to Reinhold E. Schmidt, MD, Abt. Immunologie und Transfusionmedizin, Medizinische Hochschule Hannover, Konstanty-Gutschow-Str. S,D-3000 Hannover 61, Germany. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C.section I734 solely to indicate this fact. 0 I992 by The American Society of Hematology. 0006-497119217912-0007$3.00/0 3239 From www.bloodjournal.org by guest on July 6, 2016. For personal use only. JACOBS ET AL 3240 Table 1. Characteristicsof PatientsWith Two NK Cell Populations Disease ALL ALL ALL ALL ALL AML AML AML AML AML AML CML CML CML CML CML NHL NHL NHL HD HD Sex Age BMT Time' M 34 24 33 31 24 46 26 21 46 35 29 27 36 21 35 37 30 46 26 29 19 23 40 24 26 Allo Autol Allo Allo Allo Autol Allo Autol Allo Allo Allo Allo Allo Allo Allo Allo Allo Autol Autol Autol Autol Allo Allo Allo Allo 54 15 20 16 16 11 11 7 30 10 9 2 3 48 32 8 4 2 F F M M M F F M F M M M F F M M F M M M M.Shw. MDS M M SAA F PNH F ia 19 6 12 2 ao 2 NK Cellst 35* 52 60 51 66 74 33 41 70 40 12 24 47 46 36 64 16 37 11 34 29 53 25 75 62 CD56+dim 2075 229 522 561 340 578 1 a4 341 513 279 162 146 132 556 414 282 100 376 286 275 392 45 135 398 135 86* 41 60 ao 60 70 75 40 41 50 50 62 66 43 31 30 50 43 55 41 69 60 56 86 29 1785 94 313 449 204 405 138 136 210 139 81 91 a7 239 128 85 50 162 157 113 270 27 76 344 39 CD56tbri8ht 14$ 59 40 20 40 30 25 60 59 50 50 38 34 57 69 70 50 57 45 59 31 40 44 14 71 291 135 209 112 136 173 46 205 303 140 81 55 45 317 286 197 50 214 129 162 122 ia 59 54 96 Abbreviations: ALL, acute lymphoblastic leukemia; AML, acute myelogenous leukemia; CML, chronic myelogenous leukemia; NHL, nonHodgkin's lymphoma; HD, Hodgkin's disease; M.Schw., Morbus Schwachman; MDS, myelodysplastic syndrome; SAA, severe aplastic anemia; PNH, paroxysmal nocturnal hemoglobinuria. *Presence of both NK cell subsets in weeks. Mean duration of two NK subsets in all patients was 17 weeks. t l n all but three allogeneic transplant patients N K cells were determined for their origin by using restriction fragment length polymorphism or chromosomal analysis. In all these patients NK cells were found to be of donor origin. *Percentages of NK cells of all PBMC or their respective subsets of all NK cells. §Absolute numbers of NK cells and their subsets per microliter of blood anti-TCR2 antibody (BMA031) was a gift from Dr R. Kurrle (Behringwerke, Marburg, Germany). Tu27 (anti-p75) was generously given by Dr K. Sugamura (Tohuko University School of Medicine, Sendai, Japan). Phenotypic analysis. Phenotypic analysis was performed either by indirect immunofluorescence with fluorescein-conjugated goat antimouse F(ab')z Ig (GM-FITC; Dianova, Hamburg, Germany) or by direct immunofluorescence in two-color analysis using directly labeled antibodies. The staining procedure has been described in detail previously." Briefly, 1to 3 X 105cells/well were incubated with murine MoAbs at an optimal dilution for 30 minutes. Nonspecific binding was eliminated by mixing the samples with a 1:5 solution of a commercial intravenous IgG (Intraglobin; Biotest, Frankfurt, Germany). After three washes, direct immunofluorescence was analyzed. Samples for indirect staining were incubated for another 30 minutes with GM-FITC, washed three times, and then analyzed using a FACScan (Becton Dickinson). Cell lines. Several continuously growing cell lines were used. Cytotoxicity assays were performed using the erythromyeloid K562 line as a standard NK target. The murine lymphoma cell line L1210 was used as target in ADCC assays. Cytotoxicity assays. All cytotoxicity assays were performed in triplicates at various effector to target (E/T) ratios using V-bottom microtiter plates with 5 x lo3 51Cr-labeled target cells per well as previously described in detail.ls The medium for the cytotoxicity assays was RPMI 1640 supplemented with 5% fetal calf serum (FCS) and 1% penicillin-streptomycin. Specific cytotoxicity was measured after 4 hours of incubation at 37°C by determining the 51Cr release. Spontaneous release was determined by incubating target cells without effector cells. Maximal release was obtained by lysing target cells with the detergent NP40. Activation of NK cell subsets. NK subsets were activated for cytotoxicity assays. For this purpose, enriched NK cell subsets were cultured after magnetic bead depletion for 24 hours in RPMI 1640 supplemented with 10% pooled human serum, 1% penicillinstreptomycin, and 1% sodium pyruvate in the presence of 500 U/mL recombinant interleukin-2 (rIL-2; Cetus, Emeryville, CA) or 200 U/mL interferon y (IFNy; Biogen, Cambridge, MA) as described previo~sly.'~ Control cells were cultured without cytokines. RESULTS CD56+dimand CD56+bngh'NK cells after BMT. Phenotypic analysis of PBL after BMT showed an additional second NK cell population in about 35% of the patients. With an increase of NK cells, a CD56+dim and a CD56+bnat subset were observed (Fig 1).The phenomenon was equally distributed among autologous (7 of 20 [35%]) and allogeneic (18 of 50 [36%]) transplants, and female and male patients, respectively (Table 1).In the allogeneic transplant patients, the reconstituted NK cells were shown to be of donor origin. There was no obvious association of the appearance of this additional NK subset with any feature, From www.bloodjournal.org by guest on July 6, 2016. For personal use only. NK CELLS AFTER BONE MARROW TRANSPLANTATION CD56 C016 3241 CD3 CD2 CDlh I 'I Fig 2. Two-color fluorescence of CD56+"'OM and CD56+dimNK cells. CD56 (red) is given on the y-axis; CD2, CD3, and CD16 antigens (green) are shown on the x-axis. All CD56+"VM cells express CD2. CD3 is detected on CD56+dimcells only. CD56+dim cells are positive for CD16; CD56+brig' cells are negative for CD16. Coexpression of CD56 with the respective antigens in a normal donor is depicted in the control. fluorescence intensity -* Fig 1. (Top) A normal control exhibiting normal NK cells after staining with CD56 or CD16 MoAb. Post-BMT patients have a CD56+dim and CD56+b*M NK cell population. The time course of CD56 and CD16 expression during 9 months after BMT in one representative patient is illustrated in the lower panel. For each sample, 10.000 cells were analyzed using a FACScan. Indirect immunofluorescence was performed as described in Materials and Methods. including underlying disease, graft-versus-host disease (GVHD), viral infections, and course of reconstitution. The [email protected] could be observed for a mean period of 17 weeks in each patient (Fig 1 and Table 1). The NK cells increased to initial small proportion of CD56+bright a maximum of about 20% to 70% of all NK cells. This increase is also reflected in the absolute number of NK cells (Table 1). Finally, the CD56+hright NK cell subset disappeared. Phenovpic characteristics of the two distinct NK cell subgroups. Using two-color immunofluorescence, both NK cell subsets were characterized in more detail. Three main populations of CD56+ cells could be distinguished by comparison of the three panels in Fig 2 (A through C). The classical NKcell phenotype in the first subset was characterThe second NK cell ized as CD2+ CD3- CD16+ CD56+dim. subset was clearly different from the typical NK phenotype. These cells were CD2+ CD3- CD16- CD56+bright. A low proportion of CD56+dimcells coexpressing CD3 was not further studied because they were T cells by definition (Fig 2). Activation antigens on C D 5 W mand CD56fbnghtNK cells. When testing different activation antigens on NK cells, they cells. They were preferentially expressed by CD56+hright were CD26+ CD2R+ HLA-DR+ p75+ @-chain of IL-2 receptor [IL-%R])(Fig 3). In contrast, the a-chain of the IL-2R (CD25) could not be detected on either of these subsets at any time. In regard to other lymphocyte antigens, similarities in both NK cell populations were observed. CD8 antigen expression could be detected in both NK cell subsets with varying percentages. The T- and NK-cell- CD561COZA C056'p75 . - '1 '1 , ' I I , CD561CD26 CD56/CD25 b green fluorescence Fig 3. Activation antigens on different CD56+ NK cells. CD56+b"M NK cells express CD2R. CD26, and p75 p-chain of IL-2R. CD56+d'm NK cells do not express these activation antigens. The a-chain of the IL-2R (CD25) is not detectable on either of the NK cell subsets. From www.bloodjournal.org by guest on July 6, 2016. For personal use only. JACOBS ET AL 3242 associated antigen CD2 was equally distributed in both NK cell subsets. In Fig 4, the cell surface antigen expression of four different patients is summarized. The differences in expression of activation antigens become particularly apparent. Cytosmears showed both NK subtypes to be large granular lymphocytes (LGL), confirming the additional NK subgroup as NK cells also by morphologic criteria with typical cytoplasmaticgranules (data not shown). CD56+bnfih'N K cells exhibit low cytotoxicity. Freshly isolated PBMC and CD56+dimand CD56+hngh'cells were tested for their NK and ADCC activity. Cytotoxicity of unseparated lymphocytes against K562 and ADCC against antibody-treated L1210 showed in all patients normal values. But both NK cell types were functionally distinct when examined in detail using CD56+dimand CD56+hright cells after FACS sorting or magnetic bead enrichment. Freshly FACS-purified CD56+dimcells exhibited high NK killing and ADCC activity. It is evident that NK and ADCC killing of CI)56+hright cells is significantly lower than that of CD56+dim NK cells (Fig SA). On the other hand, after IL-2 or IFNy activation, the relative increase of cytotoxicity in these CD56+hnghtcells is higher compared with the CD56+dim cells (Fig 5B and C). T -E I I eo .-m In 2. 40 0 E g PO In 0 +IFN Fig 5. (A) NK cytotoxicity (dotted shaded bars) and ADCC (hatched shaded bars) of unseparated PBMC (left side of the figure) and FACS-sorted CD56+bdgMand CD56+dimcells. The mean values of three patients and standard errors are shown. (B) NK cytotoxicity of unseparated fresh PBMC (open bar), CD56+dh-enriched (hatched shaded bars), and CD56+"g'-enriched NK cells (shaded bars) before (medium) and after IL-2 or IFNy activation. K562 were used as target cells at an E/T ratio of 1 O : l . The mean values of five patients and standard errors are shown. (C) ADCC of unseparated fresh PBMC (open bar), CD56+dim-enriched(hatched shaded bars), and CD56+brightenriched NK cells (shaded bars) before (medium) and after IL-2 or IFNy activation. Antiserum-coated L1210 cells were used as target cells at an E/T ratio of 1 O : l . The mean values of five patients and standard errors are shown. For all panels cytotoxicity assays were performed in triplicates as described in Materials and Methods. DISCUSSION Fig 4. Coexpression of cell s ~ d a c oantigens on CD56+dim (A) and CD56*wm (6) NK cells. Each bar displays the mean of four experiments. Lines indicate standard deviations. For a number of years the CD56 or NKH-1 molecule has been shown to represent the most suitable surface antigen to identify PB NK cells.XJ" However, the functional nature of this antigen on NK cells is still a matter of discussion.'" Recently, two groups described a NK cell subset characterized by a high expression of CD56 antigen.'5.2"-2'They have observed these NK cells in normal donors representing only less than 2% of all PBL. We characterize here the CD16- CD56+brigh' NK cell subset in comparison to normal CD16+CD56+dim NK cells during reconstitution after BMT (Figs 1 and 2). The reconstitution phase after BMT, cancer finally,T-deficient treatment usingthe r1L-2,22 combined deficiencies (unpublished observations) represent clinical disease states in which high frequencies of NK From www.bloodjournal.org by guest on July 6, 2016. For personal use only. NK CELLS AFTER BONE MARROW TRANSPLANTATION 3243 cells (up t o 70% t o 90%) can b e observed. This high proportion of NK cells usually goes along with the presence of this particular [email protected] subset. Therefore, these disease entities provide models for studying activation and differentiation of human NK cells in vivo. Our phenotypic data show a much higher activation compared with CD56+d1mcells (Figs 3 status of [email protected] and 4). T h e CD16- [email protected] cells all coexpress the p75 P-chain of the IL-2R, but d o not express the high-affinity IL-2R. This finding is consistent with in vivo IL-2-activated NK cells in tumor patients.22 In earlier studies it has been cells is shown that the p75 expression on these [email protected] responsible for IL-Zdependent induction of proliferation . ~ ~ ~ ~ ~ ~it~ ~ and in vitro activation of c y t o t o x i ~ i t y Therefore, must b e concluded that chronic exposure to IL-2 in vivo may be responsible for the lack of the CD25 IL-2R. In addition, the CD26 activation antigen is expressed on all [email protected] cells. The CD56+br1ghtNK cell subset post-BMT, in contrast t o normal NK cells, does not exhibit the CD16 o r FcyRIII structure. This phenotype has also been detected for a small CD56+br1gbt subset in normals.20 It is consistent with the functional observation that these cells can hardly perform any ADCC (Fig 5A). CD2R is present on 50% of these cells. In contrast, none of these activation structures, with exception of very little p75, can be detected on CD16+ CD56+d1m NK cells. T h e cytotoxic function of CD56+br1ght cells appears to be significantly decreased compared with the CD56+d1m NK cells. But after in vitro activation using IL-2 and IFNy, cytotoxicity enhancement can b e observed for both NK subsets, relatively stronger for t h e CD56+bT1gbt cells. Interestingly, the finding of two different CD56+ cell subsets is a transient one (Fig 1). During reconstitution it can be detected during a mean period of about 4 months. A t this point, it can only b e speculated that most likely the early reconstitution of t h e lymphoid system in the presence of high cytokine concentrations, in particular IL-2, might enhance this CD56+br1ghtNK subset. The lack of CD16 expression and diminished NK cell activity suggest the cells represent a n early NK hypothesis that the CD56+br1ght progenitor cell subset that might differentiate into mature NK cells.24Alternatively, the CD16- CD56+br1ght NK cells might b e the result of a maximal in vivo activation of NK cells after BMT. This activation may induce an increased CD56 and p75 antigen expression, and a t the same time a loss of FcyRIII or CD16 antigen. Therefore, further in vitro activation and molecular studies will have to clarify the functional role of t h e two NK cell subsets expressing different CD56 antigen density. This knowledge may b e particularly important when using IL-2 treatment for patients after BMT. ACKNOWLEDGMENT We thank Dr Peter Uciechowski for help with the flow cytometric analysis and Almut Kemper for excellent technical assistance. REFERENCES 1. Trinchieri G: Biology of natural killer cells. Adv Immunol 46:" 1989 2. Hercend T, Takvorian T, Nowill A, Tantravahi R, Moingeon P, Anderson KC, Murray C, Bohuon C, Ythier A, Ritz J: Characterization of natural killer cells with antileukemia activity following bone marrow transplantation. Blood 67:722,1986 3. Robertson MJ, Ritz J: Biology and clinical relevance of human natural killer cells. Blood 76:2421,1990 4. Atkinson K Reconstitution of the hematopoietic and immune systems after marrow transplantation. Bone Marrow Transplant 5:209,1990 5. Ault KA, Antin JH, Ginsburg D, Orkin SH, Rappeport JM, Keohan ML, Martin P, Smith BR: Phenotype of recovering lymphoid cell populations after marrow transplantation. J Exp Med 161:1483,1985 6. Ritz J, Schmidt RE, Michon J, Hercend T, Schlossman SF: Characterization of functional surface structures on human natural killer cells. Adv Immunol42:181,1988 7. Hercend T, Schmidt RE: Characteristics and uses of natural killer cells. Immunol Today 10:291,1988 8. Schubert J, Lanier LL, Schmidt RE: Cluster report CD56 in Knapp W, Dorken B, Gilks WR, Rieber EP, Schmidt RE, Stein H, von dem Borne AEGKr (eds): Leucocyte Typing IV. Oxford, UK, Oxford University, 1989, p 699 9. Lanier LL, Testi R, Bindl J, Phillips JH: Identity of Leu-19 (CD56) leukocyte differentiation antigen and neural cell adhesion molecule. J Exp Med 169:2233,1989 10. Lanier LL, Chang C, Azuma M, Ruitenberg JJ, Hemperly JJ, Phillips JH: Molecular and functional analysisof human natural killer cell-associated neural cell adhesion molecule (N-CAM/ CD56). J Immunol146:4421,1991 11. Schmidt RE, Murray C, Daley JF, Schlossman SF, Ritz J: A subset of natural killer cells in peripheral blood displays a mature T cell phenotype. J Exp Med 164:351,1986 12. Anderson P, Caligiuri M, Ritz J, Schlossman SF: CD3negative natural killer cells express zeta TCR as part of a novel molecular complex. Nature 341:159, 1989 13. Werfel T, Witter W, Gotze 0: CDllb and CDllc antigens are rapidly increased on human natural killer (NK) cells upon activation. J Immunol 147:2423,1991 14. Schubert J, Heiken H, Jacobs R, Delany P, Witte T, Schmidt RE: A subset of CD16- natural killer cells without antibodydependent cellular cytotoxicity function. Nat Immun Cell Growth Regul9:103,1990 15. Nagler A, Lanier LL, Phillips JH: Constitutive expression of high affinity interleukin 2 receptors on human CD16- natural killer cells. J Exp Med 171:1527, 1990 16. Knapp W, Dorken B, Gilks WR, Rieber EP, Schmidt RE, Stein H, von dem Borne, AEGKr (eds): Leucocyte Typing IV, Oxford, UK, Oxford University, 1989 17. Schmidt RE, Hercend T, Fox DA, Bensussan A, Bartley G, Daley JF, Schlossman SF, Reinherz EL, Ritz J: The role of interleukin 2 and the T11/E rosette antigen in activation and proliferation of human NK clones. J Immunol 129:1299,1985 18. Schmidt RE, MacDermott RP, Bartley GT, Bertovich M, Amato DA, Austen KF, Schlossman SF, Stevens RL, Ritz J: Specific release of proteoglycans from human natural killer cells during target lysis. Nature 318:289,1985 19. Schmidt RE, Michon JM, Woronicz J, Schlossman SF, Reinherz EL, Ritz J: Enhancement of natural killer function through activation of the T11 E rosette receptor. J Clin Invest 79:305,1987 From www.bloodjournal.org by guest on July 6, 2016. For personal use only. 3244 20. Lanier LL, Le AM, Civin CI, Loken MR, Phillips JH: The relationship of CD16(Leu-ll) and Leu-19(NKH-I) antigen expression on human peripheral blood NK cells and cytotoxic T lymphocytes. J Immunol136:4480,1986 21. Caligiuri MA, Zmuidzinas A, Manley TJ, Levine H, Smith KA, Ritz J: Functional consequences of interleukin 2 receptor expression on resting human lymphocytes. J Exp Med 171:1509, 1990 22. Voss SD, Robb RJ, Weil-Hillman G, Hank JA, Sugamura K, Tsudo M, Sonde1 PM: Increased expression of the interleukin 2 JACOBS ET AL (IL-2) receptor p chain (p70) on CD56+ natural killer cells after in vivo IL-2 therapy: p70 expression does not alone predict the level of intermediate affinity IL-2 binding. J Exp Med 172:1101,1990 23. Gottschalk LR, Bray RA, Kaizer H, Gebel HM: Two populations of CD56(Leu-l9)+/CD16+ cells in bone marrow transplant recipients. Bone Marrow Transplant 5:259,1990 24. Nagler A, Lanier LL, Cwirla S, Phillips JH: Comparative studies of human FcRIII-positive and negative natural killer cells. J Immunol143:3183,1989 From www.bloodjournal.org by guest on July 6, 2016. For personal use only. 1992 79: 3239-3244 CD16- CD56+ natural killer cells after bone marrow transplantation R Jacobs, M Stoll, G Stratmann, R Leo, H Link and RE Schmidt Updated information and services can be found at: http://www.bloodjournal.org/content/79/12/3239.full.html Articles on similar topics can be found in the following Blood collections Information about reproducing this article in parts or in its entirety may be found online at: http://www.bloodjournal.org/site/misc/rights.xhtml#repub_requests Information about ordering reprints may be found online at: http://www.bloodjournal.org/site/misc/rights.xhtml#reprints Information about subscriptions and ASH membership may be found online at: http://www.bloodjournal.org/site/subscriptions/index.xhtml Blood (print ISSN 0006-4971, online ISSN 1528-0020), is published weekly by the American Society of Hematology, 2021 L St, NW, Suite 900, Washington DC 20036. Copyright 2011 by The American Society of Hematology; all rights reserved.