scholarly journals Deep Phenotypic Analysis of Blood and Lymphoid T and NK Cells from HIV+ Controllers and Non-Controllers

2021 ◽  
Author(s):  
Ashley F. George ◽  
Xiaoyu Luo ◽  
Jason Neidleman ◽  
Rebecca Hoh ◽  
Poonam Vohra ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Acute Infection ◽  
Lymphoid Tissues ◽  
Elite Controllers ◽  
Phenotypic Analysis ◽  
Effector Cells ◽  
Follicular Helper ◽  
Hiv Controllers

T and natural killer (NK) cells are effector cells with key roles in anti-HIV immunity, including in lymphoid tissues, the major site of HIV persistence. In this study, we used 42-parameter CyTOF to conduct deep phenotyping of paired blood- and lymph node (LN)-derived T and NK cells from three groups of HIV+ aviremic individuals: elite controllers, and antiretroviral therapy (ART)-suppressed individuals who had started therapy during chronic vs. acute infection, the latter of which is associated with better outcomes. We found that acute-treated individuals are enriched for specific subsets of T and NK cells, including blood-derived CD56-CD16+ NK cells previously associated with HIV control, and LN-derived CD4+ T follicular helper cells with heightened expansion potential. An in-depth comparison of the features of the cells from blood vs. LNs of individuals from our cohort revealed that T cells from blood were more activated than those from LNs. By contrast, LNs were enriched for follicle-homing CXCR5+ CD8+ T cells, which expressed increased levels of inhibitory receptors and markers of survival and proliferation as compared to their CXCR5- counterparts. In addition, a subset of memory-like CD56brightTCF1+ NK cells was enriched in LNs relative to blood. These results together suggest unique T and NK cell features in acute-treated individuals, and highlight the importance of examining effector cells not only in blood but also the lymphoid tissue compartment, where the reservoir mostly persists, and where these cells take on distinct phenotypic features.

Dynamic behavior of NK cells during activation in lymph nodes

Blood ◽  
2009 ◽  
Vol 114 (15) ◽  
pp. 3227-3234 ◽  
Author(s):  
Hélène Beuneu ◽  
Jacques Deguine ◽  
Béatrice Breart ◽  
Ofer Mandelboim ◽  
James P. Di Santo ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Fluorescent Proteins ◽  
Migratory Behavior ◽  
Lymphoid Tissues ◽  
Toll Like Receptor ◽  
Secondary Lymphoid Organs ◽  
Short Contacts

Abstract During infection, Toll-like receptor agonists induce natural killer (NK)–cell activation by stimulating dendritic cells (DCs) to produce cytokines and transpresent IL-15 to NK cells. Yet the cellular dynamics underlying NK-cell activation by DCs in secondary lymphoid organs are largely unknown. Here, we have visualized NK-cell activation using mice in which NK cells and DCs express different fluorescent proteins. In response to polyI:C or lipopolysaccharide, NK cells maintained a vigorous migratory behavior, establishing multiple short contacts with maturing DCs. Furthermore, mature antigen-loaded DCs that made long-lived interactions with T cells formed short-lived contacts with NK cells. The different behaviors of T cells and NK cells during activation was correlated with distinct calcium responses upon interaction with DCs. That NK cells become activated while remaining motile may constitute an efficient strategy for sampling local concentrations of cytokines around DCs in secondary lymphoid tissues.

Elevated CD54 Expression Renders CD4+ T Cells Susceptible to Natural Killer Cell-Mediated Killing

2019 ◽  
Vol 220 (12) ◽  
pp. 1892-1903 ◽  
Author(s):  
Xi Chen ◽  
Huihui Chen ◽  
Zining Zhang ◽  
Yajing Fu ◽  
Xiaoxu Han ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cd4 T Cells ◽  
Nk Cell ◽  
Killer Cell ◽  
Adaptive Immune Response ◽  
Phenotypic Analysis

Abstract Background Natural killer (NK) cells are an important type of effector cell in the innate immune response, and also have a role in regulation of the adaptive immune response. Several studies have indicated that NK cells may influence CD4+ T cells during HIV infection. Methods In total, 51 HIV-infected individuals and 15 healthy controls participated in this study. We performed the flow cytometry assays and real-time PCR for the phenotypic analysis and the functional assays of NK cell-mediated deletion of CD4+ T cells, phosphorylation of nuclear factor-κB (NF-κB/p65) and the intervention of metformin. Results Here we detected high CD54 expression on CD4+ T cells in HIV-infected individuals, and demonstrate that upregulated CD54 is associated with disease progression in individuals infected with HIV. We also show that CD54 expression leads to the deletion of CD4+ T cells by NK cells in vitro, and that this is modulated by NF-κB/p65 signaling. Further, we demonstrate that metformin can suppress CD54 expression on CD4+ T cells by inhibiting NF-κB/p65 phosphorylation. Conclusions Our data suggest that further studies to evaluate the potential role of metformin as adjunctive therapy to reconstitute immune function in HIV-infected individuals are warranted.

scholarly journals Granulocyte Colony-Stimulating Factor Effectively Mobilizes TCR γδ and NK Cells Providing an Allograft Potentially Enhanced for the Graft-Versus-Leukemia Effect for Allogeneic Stem Cell Transplantation

2021 ◽  
Vol 12 ◽  
Author(s):  
Lia Minculescu ◽  
Henrik Sengelov ◽  
Hanne Vibeke Marquart ◽  
Lars Peter Ryder ◽  
Anne Fischer-Nielsen ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Nk Cells ◽  
Peripheral Blood ◽  
Nk Cell ◽  
Cell Compartment ◽  
Effector Cells ◽  
Graft Versus Leukemia ◽  
Hla Dr

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potential cure for patients with hematological malignancies but substantial risks of recurrence of the malignant disease remain. TCR γδ and NK cells are perceived as potent innate effector cells in HSCT and have been associated with post-transplant protection from relapse in clinical studies. Immunocompetent cells from the donor are crucial for patient outcomes and peripheral blood stem cells (PBSC) are being increasingly applied as graft source. G-CSF is the preferential mobilizing agent in healthy donors for PBSC grafts, yet effects of G-CSF on TCR γδ and NK cells are scarcely uncovered and could influence the graft composition and potency of these cells. Therefore, we analyzed T and NK cell subsets and activation markers in peripheral blood samples of 49 donors before and after G-CSF mobilization and—for a subset of donors—also in the corresponding graft samples using multicolor flowcytometry with staining for CD3, CD4, CD8, TCRαβ, TCRγδ, Vδ1, Vδ2, HLA-DR, CD45RA, CD197, CD45RO, HLA-DR, CD16, CD56, and CD314. We found that TCR γδ cells were mobilized and harvested with an efficiency corresponding that of TCR αβ cells. For TCR γδ as well as for TCR αβ cells, G-CSF preferentially mobilized naïve and terminally differentiated effector (TEMRA) cells over memory cells. In the TCR γδ cell compartment, G-CSF preferentially mobilized cells of the nonVδ2 types and increased the fraction of HLA-DR positive TCR γδ cells. For NK cells, mobilization by G-CSF was increased compared to that of T cells, yet NK cells appeared to be less efficiently harvested than T cells. In the NK cell compartment, G-CSF-stimulation preserved the proportion of CD56dim NK effector cells which have been associated with relapse protection. The expression of the activating receptor NKG2D implied in anti-leukemic responses, was significantly increased in both CD56dim and CD56bright NK cells after G-CSF stimulation. These results indicate differentiated mobilization and altering properties of G-CSF which could improve the effects of donor TCR γδ and NK cells in the processes of graft-versus-leukemia for relapse prevention after HSCT.

Fusion Proteins of Ligands for NKG2D and CD20-Directed ScFvs Sensitize Lymphomas for NK Cell-Mediated Lysis

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2843-2843
Author(s):  
Christian Kellner ◽  
Daniela Hallack ◽  
Pia Glorius ◽  
Matthias Staudinger ◽  
Sahar Mohseni Nodehi ◽  
...  
Keyword(s):  
T Cells ◽  
B Cell ◽  
Nk Cells ◽  
Natural Killer ◽  
Tumor Cells ◽  
Mhc Class I ◽  
Fusion Proteins ◽  
Nk Cell ◽  
Effector Cells ◽  
Healthy Donors

Abstract Abstract 2843 Natural killer group 2 member D (NKG2D) is an important activating receptor controlling cytotoxicity of natural killer (NK) cells and T cells and plays an important role in immune surveillance against tumors. For redirecting NK cells to B-lymphoid tumor cells two recombinant bifunctional antibody-based fusion proteins were designed in order to coat malignant cells with ligands for NKG2D and attract NK cells. Therefore, a human CD20-directed single-chain fragment variable (scFv) was fused to NKG2D-specific ligands, either MHC class I chain-related protein A (MICA) or unique long 16-binding protein 2 (ULBP2). These two fully human fusion proteins, designated MICA:CD20 and ULBP2:CD20, respectively, were expressed in eukaryotic cells and purified to homogeneity. Size exclusion chromatography revealed that both purified proteins predominantly formed monomers. MICA:CD20 and ULBP2:CD20 specifically and simultaneously bound to CD20 and NKG2D and efficiently mediated lysis of lymphoma cell lines with mononuclear cells from healthy donors as effector cells. Analysis of the activation status of NKG2D-positive T cells and NK cells revealed that MICA:CD20 and ULBP2:CD20 activated resting NK cells, but not T cells, indicating that NK cells were the relevant effector cell population for the two molecules. In cytotoxicity assays using human NK cells from healthy donors, both agents sensitized lymphoma cell lines as well as fresh tumor cells for NK cell-mediated lysis. MICA:CD20 and ULBP2:CD20 induced lysis at low nanomolar concentrations with half maximum effective concentrations between 1 and 4 nM depending on target cells. Interestingly, ULBP2:CD20 exhibited a higher cytolytic potential than MICA:CD20 in terms of maximum lysis. Importantly, MICA:CD20 and ULBP2:CD20 induced lysis of 13/13 tested primary tumor cell samples from patients with different B cell malignancies including chronic lymphocytic leukemia, mantle cell lymphoma and marginal zone lymphoma. Interestingly, cell surface expression of endogenous MICA and ULBP2 was low or not detectable on fresh tumor cells. In addition, ULBP2:CD20 was also capable of inducing lysis of tumor cells in cytotoxicity experiments using autologous patient-derived NK cells as effector cells, indicating that the triggering signal was sufficient to overcome inhibition by interactions between killer cell immunoglobulin-like receptors and MHC class I molecules. Moreover, both MICA:CD20 and ULBP2:CD20 synergistically enhanced antibody-dependent cellular cytotoxicity (ADCC) by the monoclonal antibody daratumumab directed against CD38 which is co-expressed together with CD20 on certain B cell lymphomas. This approach of simultaneously triggering ADCC and natural cytotoxicity by these bifunctional fusion proteins may represent a promising strategy to achieve stronger NK cell-mediated antitumor responses. Disclosures: de Weers: Genmab : Employment. van De Winkel:Genmab: Employment. Parren:Genmab: Employment.

scholarly journals Radiation sensitivity of resting and activated nonspecific cytotoxic cells of T lineage and NK lineage

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1615-1621 ◽  
Author(s):  
D Zarcone ◽  
AB Tilden ◽  
VG Lane ◽  
CE Grossi
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Radiation Sensitivity ◽  
Lak Cells ◽  
Activated T Cells ◽  
Effector Cells ◽  
Blood Lymphocytes ◽  
Nonspecific Cytotoxicity ◽  
Cytotoxic Function

Natural killer (NK) cell-mediated killing of tumor cells is a radiation- sensitive function that in most subjects is completely abrogated by treatment of the effector cells with 3,000 cGy. The radiation sensitivity of LAK (lymphokine-activated killer) cells and their precursors, the bulk of which are NK cells, is undetermined. In this study, functional cytotoxicity assays and electron microscopy were used to determine the effect of radiation on the cytotoxic function of NK cells, LAK cells (generated by three-day culture of peripheral blood lymphocytes with IL-2), and LAK cell precursors (lymphocytes irradiated prior to culture with IL-2). For comparison, we analyzed the radiation sensitivity of lectin-dependent cell-mediated cytotoxicity (LDCC), which is primarily a function of CD3+ CD8+ granular lymphocytes. We also analyzed the radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells (AK activity). Following 3,000 cGy irradiation, NK cells retained their ability to bind to tumor cell targets but, as shown by both morphologic and functional analyses, they did not undergo activation after conjugate formation, and were unable to release the content of their granules. In order to evaluate LDCC, lymphocytes were depleted of CD16+ cells and tested in a cytotoxicity assay in the presence of Con A. The radiation sensitivity curve was comparable to that of NK cell-mediated cytotoxicity. IL-2-treated lymphocytes (LAK cells) were relatively radioresistant as compared with untreated NK cells, and their cytotoxic function was not abrogated until treatment with greater than 10,000 cGy. Cells receiving such radiation doses displayed cytoplasmic blebbing and damage of their cytoskeletal structures, with disruption of centrioles and microtubules, and disarray of the intermediate filaments. As was shown with NK cells, irradiated LAK cells formed conjugates with tumor targets but failed to degranulate. The radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells was identical to that of LAK effector cells. Doses up to 2,000 cGy did not prevent generation of LAK cells from blood lymphocytes, but 3,000 cGy did so. Blast transformation similar to that observed in IL-2- stimulated controls occurred when lymphocytes irradiated with 3,000 cGy were cultured with IL-2. These transformed cells were not cytotoxic and displayed a normal cytoskeletal apparatus but did not bear electron- dense granules.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Umbilical cord blood-derived ILC1-like cells constitute a novel precursor for mature KIR+NKG2A- NK cells

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Sabrina Bianca Bennstein ◽  
Sandra Weinhold ◽  
Angela Riccarda Manser ◽  
Nadine Scherenschlich ◽  
Angela Noll ◽  
...  
Keyword(s):  
Cord Blood ◽  
Nk Cells ◽  
Umbilical Cord ◽  
Umbilical Cord Blood ◽  
Nk Cell ◽  
Functional Characterization ◽  
Lymphoid Tissues ◽  
The Novel ◽  
Effector Cells ◽  
Notch Ligands

Despite their identification several years ago, molecular identity and developmental relation between human ILC1 and NK cells, comprising group 1 ILCs, is still elusive. To unravel their connection, thorough transcriptional, epigenetic, and functional characterization was performed from umbilical cord blood (CB). Unexpectedly, ILC1-like cells lacked Tbet expression and failed to produce IFNγ. Moreover, in contrast to previously described ILC1 subsets they could be efficiently differentiated into NK cells. These were characterized by highly diversified KIR repertoires including late stage NKG2A-KIR+ effector cells that are commonly not generated from previously known NK cell progenitor sources. This property was dependent on stroma cell-derived Notch ligands. The frequency of the novel ILC1-like NK cell progenitor (NKP) significantly declined in CB from early to late gestational age. The study supports a model in which circulating fetal ILC1-like NKPs travel to secondary lymphoid tissues to initiate the formation of diversified NK cell repertoires after birth.

Donor’s NK Cells May Influence the Engraftment in Pediatrics Patients after T-Cell Depleted Haploidentical Stem Cell Transplant for Thalassemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4595-4595
Author(s):  
Antonella Isgro ◽  
Marco Marziali ◽  
Pietro Sodani ◽  
Javid Gaziev ◽  
Paola Polchi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Hla Class I ◽  
Mixed Chimerism ◽  
Effector Cells ◽  
Post Transplant

Abstract In haploidentical hematopoietic transplantation, donor-versus-recipient NK cell alloreactivity derives from a mismatch between donor NK clones bearing inhibitory Killer Cell Ig-like Receptors (KIRs) for self HLA class I molecules and their HLA class I ligands (KIR ligands) on recipient cells. The mechanism whereby alloreactive NK cells exert their benefits in transplantation has been elucidated. The infusion of alloreactive NK cells ablates recipient T cells which reject the graft, and ablates recipient dendritic cells (DCs) which trigger GvHD, thus protecting from GvHD (Ruggeri et al., Science 2002). NK cell alloreactivity also boosts very rapid rebuilding of donor adaptive immunity to infections. In this study we analysed the potential role of NK cells after haploidentical transplant in b-thalassemia patients. T and B cell depletion was carried out with CD34+ coated magnetic microbeads and the CliniMACS device (Miltenyi Biotec©) from peripheral blood and bone marrow of donors (the mothers) and resulted in grafts consisting of stem cells and effector cells (NK cells, monocytes) with the addition of bone marrow mononuclear cells (BMMNCs 3 × 105/kg of the recipient). A total of 11 pediatric patients with b-thalassemia received T and B cell depleted transplants from their haploidentical mothers with a median number of 15 ×106 CD34 stem cells. To analyse the mechanisms involved in immunological reconstitution post transplant, we analysed T cell subsets by flow cytometry, particularly NK sets (CD3- CD56+, CD3− CD16+ and CD56+CD16+ NK cells) at day + 20 and + 60 post transplant. Day + 20 post transplant, the patients had significantly lower CD4+ T cells in comparison to the controls (1.9 ± 1.4% vs. 47.5 ± 6% respectively), whereas CD8+ T cells numbers did not statistically differ between patients and controls (24.2 ± 33.7% vs. 20 ± 7%). NK cells were among the first lymphocytes to repopulate the peripheral blood, and up to 70% of these cells were CD3-CD56+bright cells. Interestingly, a direct correlation has been observed between the percentages of CD56+CD16+ NK subset and the BM engraftment (in mean 71 ± 21% CD56+CD16+ in the four patients with full engraftment, 27 ± 28% in the three patients with a stable mixed chimerism after BM transplant (70–80% of donor cells) and 1.4 ± 1% in the four patients with rejection). In all the patients the origin of the NK subsets was from the mothers. Day + 60 post transplant an increase in the percentages of CD4+ T cells, naïve CD4+ cells and in thymic naïve Th cells were observed (3 ± 1.2%, 2.9 ± 2.1%, 2.7 ± 1%, respectively). CD8+ T cells were also increased (in mean 35 ± 27.5%), in parallel with the increase of the CD3-CD16+ NK cells (potent cytotoxic effector cells) especially in the patients with full engraftment (in mean 47 ± 20% vs. 28 ± 31% in mixed chimerism) NK CD56+bright cells develop more rapidly than other lymphocytes, but CD16+ NK cells (with cytotoxic potential) require more prolonged exposure to maturation factor (IL-2) in the bone marrow. Interestingly we observed higher percentages of NK subsets just twenty days post transplant in the patients with full engraftment respect the mixed chimerism and the rejection, suggesting a role of donor NK cells on improved engraftment and on prevention of the rejection with the attack of the host lympho-hematopoietic cells. These observations may suggest the importance of NK subsets analyses at the first time of the transplant as an useful parameter for the outcome of the transplant and/or the use of donor’s alloreactive NK cells especially in haploidentical recipients.

scholarly journals Preservation of Peripheral T Follicular Helper Cell Function in HIV Controllers

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Supranee Buranapraditkun ◽  
Franco Pissani ◽  
Jeffrey E. Teigler ◽  
Bruce T. Schultz ◽  
Galit Alter ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cell Maturation ◽  
Elite Controllers ◽  
Follicular Helper ◽  
B Cell Maturation ◽  
B Cell Memory ◽  
Interleukin 21 ◽  
Hiv Controllers

ABSTRACT The maturation process of high-affinity antibodies is a result of intricate interactions between B cells and follicular helper T (Tfh) cells occurring in lymphoid germinal centers. HIV infection induces significant chronic immune activation, phenotypic skewing, and inflammation driven by years of continuous viral replication. High levels of viremia as well as immune activation and dysfunction have been demonstrated to have a perturbing impact on the B cell memory compartment and contribute to B cell exhaustion. Counterintuitively, the factors associated with perturbation of the B cell compartment seem to be favorable for the generation of highly affinity-matured Env-specific antibodies in a minority of HIV-infected individuals. Thus, the impact of HIV antigenemia on B cells and Tfh cell interactions warrants further exploration. We therefore studied immunophenotypes of HIV-specific B cells in individuals with differing levels of viral control using HIV Env gp120 probes and characterized the functionality of matched T cells in peripheral blood. While CXCR5+ CD4+ T cells were significantly diminished in HIV progressors, we found that a small subset of gp120-specific interleukin-21 (IL-21)-secreting CXCR5+ CD4+ T cells were significantly associated with gp120-specific B cell frequencies. In contrast, neither bulk CXCR5+ CD4+ T cells nor other HIV antigen specificities were associated with gp120-specific B cell levels. HIV-specific B cells derived from elite controllers displayed greater amounts of gp120-specific B cells in the resting memory subset, whereas HIV-specific B cells in progressors accumulated in tissue-like and activated memory subsets. Furthermore, CXCR5+ CD4+ T cells from elite controllers showed a stronger ex vivo capacity to induce B cell maturation and immunoglobulin class switching than cells from HIV progressors. IMPORTANCE Dissecting the factors that are involved in B cell maturation and antibody development is important for HIV vaccine design. In this study, we found that HIV Env-specific CXCR5+ CD4+ T cells that secrete interleukin-21 are strongly associated with B cell memory phenotypes and function. Moreover, we found that the immune responses of HIV controllers showed intrinsically better helper activity than those of HIV progressors.

scholarly journals Natural killer cell immunosuppressive function requires CXCR3-dependent redistribution within lymphoid tissues

2021 ◽  
Author(s):  
Ayad Ali ◽  
Laura M Canaday ◽  
H Alex Feldman ◽  
Hilal Cevik ◽  
MIchael T Moran ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Migration ◽  
T Cell ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Lymphoid Tissues ◽  
Type I ◽  
Type I Ifn ◽  
Cell Suppression

Natural killer (NK) cell suppression of T cells is a key determinant of viral pathogenesis and vaccine efficacy. This process involves perforin-dependent elimination of activated CD4 T cells during the first three days of infection. Although this mechanism requires cell-cell contact, NK cells and T cells typically reside in different compartments of lymphoid tissues at steady state. Here, we show that NK-cell suppression of T cells is associated with a transient accumulation of NK cells within T cell-rich sites of the spleen during lymphocytic choriomeningitis virus infection. The chemokine receptor CXCR3 is required for relocation to T-cell zones and suppression of antiviral T cells. Accordingly, this NK-cell migration is mediated by type I interferon (IFN)-dependent promotion of CXCR3 ligand expression. In contrast, adenoviral vectors that weakly induce type I IFN and do not stimulate NK-cell inhibition of T cells also do not promote measurable redistribution of NK cells to T-cell zones. Provision of supplemental IFN could rescue NK-cell migration during adenoviral vector immunization. Thus, type I IFN and CXCR3 are critical for properly positioning NK cells to constrain antiviral T-cell responses. Development of strategies to curtail migration of NK cells between lymphoid compartments may enhance vaccine-elicited immune responses.

scholarly journals Radiation sensitivity of resting and activated nonspecific cytotoxic cells of T lineage and NK lineage

Blood ◽  
1989 ◽  
Vol 73 (6) ◽  
pp. 1615-1621 ◽  
Author(s):  
D Zarcone ◽  
AB Tilden ◽  
VG Lane ◽  
CE Grossi
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Radiation Sensitivity ◽  
Lak Cells ◽  
Activated T Cells ◽  
Effector Cells ◽  
Blood Lymphocytes ◽  
Nonspecific Cytotoxicity ◽  
Cytotoxic Function

Abstract Natural killer (NK) cell-mediated killing of tumor cells is a radiation- sensitive function that in most subjects is completely abrogated by treatment of the effector cells with 3,000 cGy. The radiation sensitivity of LAK (lymphokine-activated killer) cells and their precursors, the bulk of which are NK cells, is undetermined. In this study, functional cytotoxicity assays and electron microscopy were used to determine the effect of radiation on the cytotoxic function of NK cells, LAK cells (generated by three-day culture of peripheral blood lymphocytes with IL-2), and LAK cell precursors (lymphocytes irradiated prior to culture with IL-2). For comparison, we analyzed the radiation sensitivity of lectin-dependent cell-mediated cytotoxicity (LDCC), which is primarily a function of CD3+ CD8+ granular lymphocytes. We also analyzed the radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells (AK activity). Following 3,000 cGy irradiation, NK cells retained their ability to bind to tumor cell targets but, as shown by both morphologic and functional analyses, they did not undergo activation after conjugate formation, and were unable to release the content of their granules. In order to evaluate LDCC, lymphocytes were depleted of CD16+ cells and tested in a cytotoxicity assay in the presence of Con A. The radiation sensitivity curve was comparable to that of NK cell-mediated cytotoxicity. IL-2-treated lymphocytes (LAK cells) were relatively radioresistant as compared with untreated NK cells, and their cytotoxic function was not abrogated until treatment with greater than 10,000 cGy. Cells receiving such radiation doses displayed cytoplasmic blebbing and damage of their cytoskeletal structures, with disruption of centrioles and microtubules, and disarray of the intermediate filaments. As was shown with NK cells, irradiated LAK cells formed conjugates with tumor targets but failed to degranulate. The radiation sensitivity of nonspecific cytotoxicity mediated by mitogen-activated T cells was identical to that of LAK effector cells. Doses up to 2,000 cGy did not prevent generation of LAK cells from blood lymphocytes, but 3,000 cGy did so. Blast transformation similar to that observed in IL-2- stimulated controls occurred when lymphocytes irradiated with 3,000 cGy were cultured with IL-2. These transformed cells were not cytotoxic and displayed a normal cytoskeletal apparatus but did not bear electron- dense granules.(ABSTRACT TRUNCATED AT 400 WORDS)

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