Characterization of human granular lymphocyte subpopulations expressing HNK-1 (Leu-7) and Leu-11 antigens in the blood and lymphoid tissues from fetuses, neonates and adults

Natural Killer T-like Cells: Immunobiology and Role in Disease

CD56+ T cells are generally recognized as a distinct population of T cells and are categorized as NKT-like cells. Although our understanding of NKT-like cells is far from satisfactory, it has been shown that aging and a number of disease situations have impacted these cells. To construct an overview of what is currently known, we reviewed the literature on human NKT-like cells. NKT-like cells are highly differentiated T cells with "CD1d-independent" antigen recognition and MHC-unrestricted cell killing. The genesis of NKT-like cells is unclear; however, it is proposed that the acquisition of innate characteristics by T cells could represent a remodeling process leading to successful aging. Additionally, it has been shown that NKT-like cells may play a significant role in several pathological conditions, making it necessary to comprehend whether these cells might function as prognostic markers. The quantification and characterization of these cells might serve as a cutting-edge indicator of individual immune health. Additionally, exploring the mechanisms that can control their killing activity in different contexts may therefore result in innovative therapeutic alternatives in a wide range of disease settings.

High Numbers of Circulating CD57+ NK Cells Associate with Resistance to HER2-Specific Therapeutic Antibodies in HER2+ Primary Breast Cancer

Natural killer (NK) cells can orchestrate effective antitumor immunity. The presence of tumor-infiltrating NK cells in diagnostic biopsies predicts pathologic complete response (pCR) to HER2-specific therapeutic antibodies in patients with primary breast cancer. Here, we analyzed whether diversity in circulating NK cells might influence tumor infiltration and HER2-specific therapeutic antibody efficacy. We found that numbers of circulating CD57⁺ NK cells inversely correlated with pCR to HER2-specific antibody treatment in patients with primary breast cancer independently of age, traditional clinicopathologic factors, and CD16A 158F/V genotype. This association was uncoupled from the expression of other NK-cell receptors, the presence of adaptive NK cells, or changes in major T-cell subsets, reminiscent of cytomegalovirus-induced immunomodulation. NK-cell activation against trastuzumab-coated HER2⁺ breast cancer cells was comparable in patients with high and low proportions of CD57⁺ NK cells. However, circulating CD57⁺ NK cells displayed decreased CXCR3 expression and CD16A-induced IL2-dependent proliferation in vitro Presence of CD57⁺ NK cells was reduced in breast tumor-associated infiltrates as compared with paired peripheral blood samples, suggesting deficient homing, proliferation, and/or survival of NK cells in the tumor niche. Indeed, numbers of circulating CD57⁺ were inversely related to tumor-infiltrating NK-cell numbers. Our data reveal that NK-cell differentiation influences their antitumor potential and that CD57⁺ NK cells may be a biomarker useful for tailoring HER2 antibody-based therapeutic strategies in breast cancer.

Varicella zoster virus productively infects human natural killer cells and manipulates phenotype

Varicella zoster virus (VZV) is a ubiquitous human alphaherpesvirus, responsible for varicella upon primary infection and herpes zoster following reactivation from latency. To establish lifelong infection, VZV employs strategies to evade and manipulate the immune system to its advantage in disseminating virus. As innate lymphocytes, natural killer (NK) cells are part of the early immune response to infection, and have been implicated in controlling VZV infection in patients. Understanding of how VZV directly interacts with NK cells, however, has not been investigated in detail. In this study, we provide the first evidence that VZV is capable of infecting human NK cells from peripheral blood in vitro. VZV infection of NK cells is productive, supporting the full kinetic cascade of viral gene expression and producing new infectious virus which was transmitted to epithelial cells in culture. We determined by flow cytometry that NK cell infection with VZV was not only preferential for the mature CD56^dim NK cell subset, but also drove acquisition of the terminally-differentiated maturity marker CD57. Interpretation of high dimensional flow cytometry data with tSNE analysis revealed that culture of NK cells with VZV also induced a potent loss of expression of the low-affinity IgG Fc receptor CD16 on the cell surface. Notably, VZV infection of NK cells upregulated surface expression of chemokine receptors associated with trafficking to the skin –a crucial site in VZV disease where highly infectious lesions develop. We demonstrate that VZV actively manipulates the NK cell phenotype through productive infection, and propose a potential role for NK cells in VZV pathogenesis.

Varicella zoster virus (VZV) is a pervasive pathogen, causing chickenpox during primary infection and shingles when the virus reactivates from latency. VZV is therefore a lifelong infection for humans, warranting investigation of how this virus interacts with the immune system. One of the first immune cells to respond to viral infection are natural killer (NK) cells, yet little is known about how VZV interacts with NK cells. We demonstrate for the first time that VZV infects human blood NK cells and can use them to pass on infection to other cells in culture. Furthermore, VZV displays a predilection for infecting mature NK cells, and amplifies expression of receptors that would promote trafficking to the skin– the site of highly infectious lesions during chickenpox and shingles. Our findings suggest a role for NK cells in VZV disease and enhances our understanding of how lifelong infections interact with the human immune system.

Chimeric Antigen Receptor Expressing Natural Killer Cells for the Immunotherapy of Cancer

Adoptive cell therapy has emerged as a powerful treatment for advanced cancers resistant to conventional agents. Most notable are the remarkable responses seen in patients receiving autologous CD19-redirected chimeric antigen receptor (CAR) T cells for the treatment of B lymphoid malignancies; however, the generation of autologous products for each patient is logistically cumbersome and has restricted widespread clinical use. A banked allogeneic product has the potential to overcome these limitations, yet allogeneic T-cells (even if human leukocyte antigen-matched) carry a major risk of graft-versus-host disease (GVHD). Natural killer (NK) cells are bone marrow-derived innate lymphocytes that can eliminate tumors directly, with their activity governed by the integration of signals from activating and inhibitory receptors and from cytokines including IL-15, IL-12, and IL-18. NK cells do not cause GVHD or other alloimmune or autoimmune toxicities and thus, can provide a potential source of allogeneic “off-the-shelf” cellular therapy, mediating major anti-tumor effects without inducing potentially lethal alloreactivity such as GVHD. Given the multiple unique advantages of NK cells, researchers are now exploring the use of CAR-engineered NK cells for the treatment of various hematological and non-hematological malignancies. Herein, we review preclinical data on the development of CAR-NK cells, advantages, disadvantages, and current obstacles to their clinical use.

Multicolor flow cytometric analysis of TLR2 and TLR9 expression and function in NK cells from patients with ANCA-associated vasculitis

BACKGROUND

The primary objective of this study was to provide an assessment of NK cells in patients with ANCA-associated vasculitis (AAV).

METHODS

Patients were classified based on the presence or absence of ANCAs and compared with healthy controls (HCs). By multiparameter flow cytometry, we evaluated the number and proportion of NK cells (CD3-CD56+) and the CD56^dim , CD56^bright , CD56^dim CD57^bright subsets; TLR2 and TLR9 expression; intracellular IFN-γ production upon stimulation with TLR2 and TLR9 ligands; degranulation activity; serum cytokines; immunohistochemical staining of available biopsies.

RESULTS

No differences in the number and proportion of NK cells between patients and HC were observed, except for a lower proportion of CD56^dim subset in ANCA-negative patients than in HC (P = 0.02). With respect to HC, TLR2 expression levels were reduced in NK cells from ANCA-negative patients (P = 0.03), in the CD56^dim subset of ANCA-positive (P = 0.02) and ANCA-negative patients (P = 0.01), in the CD56^bright subset of ANCA-positive patients (P = 0.007), and in the CD56^dim CD57^bright subset of ANCA-positive (P = 0.04) and ANCA-negative patients (P = 0.03). No differences between patients and HC were found concerning IFN-γ production and degranulation activity. IL-22 levels were lower in ANCA-positive patients than in HC (P = 0.01). The immunohistochemical analysis showed sporadic CD56+ cells in one renal biopsy, and a diffuse and moderate infiltrate of IL-22+ cells in all renal biopsies and in skin tissue.

CONCLUSIONS

Our data suggest a role of infectious stimuli triggering NK cells in AAV pathogenesis. Poor detection of NK cells in affected tissues suggests a marginal involvement in local inflammatory responses. © 2017 International Clinical Cytometry Society.

GSK3 Inhibition Drives Maturation of NK Cells and Enhances Their Antitumor Activity

Maturation of human natural killer (NK) cells as defined by accumulation of cell-surface expression of CD57 is associated with increased cytotoxic character and TNF and IFNγ production upon target-cell recognition. Notably, multiple studies point to a unique role for CD57⁺ NK cells in cancer immunosurveillance, yet there is scant information about how they mature. In this study, we show that pharmacologic inhibition of GSK3 kinase in peripheral blood NK cells expanded ex vivo with IL15 greatly enhances CD57 upregulation and late-stage maturation. GSK3 inhibition elevated the expression of several transcription factors associated with late-stage NK-cell maturation including T-BET, ZEB2, and BLIMP-1 without affecting viability or proliferation. When exposed to human cancer cells, NK cell expanded ex vivo in the presence of a GSK3 inhibitor exhibited significantly higher production of TNF and IFNγ, elevated natural cytotoxicity, and increased antibody-dependent cellular cytotoxicity. In an established mouse xenograft model of ovarian cancer, adoptive transfer of NK cells conditioned in the same way also displayed more robust and durable tumor control. Our findings show how GSK3 kinase inhibition can greatly enhance the mature character of NK cells most desired for effective cancer immunotherapy. Cancer Res; 77(20); 5664-75. ©2017 AACR.

Human Natural Killer cell expression of ULBP2 is associated with a mature functional phenotype

NKG2D is an important activating receptor expressed on NK cells. Ligands (termed NKG2DL) for this receptor include ULBP1-6, MICA and MICB in humans; they are upregulated in stressed, cancerous or infected cells where they engage NKG2D to induce NK cell cytotoxicity and cytokine production. Expression of NKG2DL on effector cells has been described in mice and more recently in human cells. We confirm that NK cell lines and IL-2 stimulated primary human NK cells also express the NKG2DL, ULBP2. However, expression of ULBP2 was not a result of transfer from a non-NK cell to an NK cell and in contrast to recent reports we saw no evidence that ULBP2 expression targeted these NK cells for fratricide or for cytotoxicity by NKG2D-expressing, non-NK effector cells. ULBP2 expression was however linked to expression of mature CD57(+) NK cells. In particular, expression of ULBP2 was strongest on those NK cells that had evidence of recent activation and proliferation. We suggest that ULBP2 could be used to identify recently activated "mature" NK cells. Defining this phenotype would be useful for understanding the ontogeny on human NK cells.

Cord Blood as a Source of Natural Killer Cells

Cord blood (CB) offers several unique advantages as a graft source for hematopoietic stem cell transplantation (HSCT). The risk of relapse and graft vs. host disease after cord blood transplantation (CBT) is lower than what is typically observed after other graft sources with a similar degree of human leukocyte antigen mismatch. Natural killer (NK) cells have a well-defined role in both innate and adaptive immunity and as the first lymphocytes to reconstitute after HSCT and CBT, and they play a significant role in protection against early relapse. In this article, we highlight the uses of CB NK cells in transplantation and adoptive immunotherapy. First, we will describe differences in the phenotype and functional characteristics of NK cells in CB as compared with peripheral blood. Then, we will review some of the obstacles we face in using resting CB NK cells for adoptive immunotherapy, and discuss methods to overcome them. We will review the current literature on killer-cell immunoglobulin-like receptors ligand mismatch and outcomes after CBT. Finally, we will touch on current strategies for the use of CB NK cells in cellular immunotherapy.

Functional Significance of CD57 Expression on Human NK Cells and Relevance to Disease

Historically, human NK cells have been identified as CD3(-)CD56(+)CD16(±) lymphocytes. More recently it has been established that CD57 expression defines functionally discrete sub-populations of NK cells. On T cells, CD57 expression has been regarded as a marker of terminal differentiation and (perhaps wrongly) of anergy and senescence. Similarly, CD57 expression seems to identify the final stages of peripheral NK cell maturation; its expression increases with age and is associated with chronic infections, particularly human cytomegalovirus infection. However, CD57(+) NK cells are highly cytotoxic and their presence seems to be beneficial in a number of non-communicable diseases. The purpose of this article is to review our current understanding of CD57 expression as a marker of NK cell function and disease prognosis, as well as to outline areas for further research.

Proteome analysis of distinct developmental stages of human natural killer (NK) cells

The recent Natural Killer (NK) cell maturation model postulates that CD34(+) hematopoietic stem cells (HSC) first develop into CD56(bright) NK cells, then into CD56(dim)CD57(-) and finally into terminally maturated CD56(dim)CD57(+). The molecular mechanisms of human NK cell differentiation and maturation however are incompletely characterized. Here we present a proteome analysis of distinct developmental stages of human primary NK cells, isolated from healthy human blood donors. Peptide sequencing was used to comparatively analyze CD56(bright) NK cells versus CD56(dim) NK cells and CD56(dim)CD57(-) NK cells versus CD56(dim)CD57(+) NK cells and revealed distinct protein signatures for all of these subsets. Quantitative data for about 3400 proteins were obtained and support the current differentiation model. Furthermore, 11 donor-independently, but developmental stage specifically regulated proteins so far undescribed in NK cells were revealed, which may contribute to NK cell development and may elucidate a molecular source for NK cell effector functions. Among those proteins, S100A4 (Calvasculin) and S100A6 (Calcyclin) were selected to study their dynamic subcellular localization. Upon activation of human primary NK cells, both proteins are recruited into the immune synapse (NKIS), where they colocalize with myosin IIa.

NK cells and immune "memory"

Immunological memory is a hallmark of the adaptive immune system. However, the ability to remember and respond more robustly against a second encounter with the same pathogen has been described in organisms lacking T and B cells. Recently, NK cells have been shown to mediate Ag-specific recall responses in several different model systems. Although NK cells do not rearrange the genes encoding their activating receptors, NK cells experience a selective education process during development, undergo a clonal-like expansion during virus infection, generate long-lived progeny (i.e., memory cells), and mediate more efficacious secondary responses against previously encountered pathogens--all characteristics previously ascribed only to T and B cells in mammals. This review describes past findings leading up to these new discoveries, summarizes the evidence for and characteristics of NK cell memory, and discusses the attempts and future challenges to identify these long-lived memory NK cell populations in humans.

CD57 defines a functionally distinct population of mature NK cells in the human CD56dimCD16+ NK-cell subset

Natural killer (NK) cells are innate immune lymphocytes that express a heterogeneous repertoire of germline-encoded receptors and undergo a distinct pattern of maturation. CD57 is a marker of terminal differentiation on human CD8(+) T cells. Very few newborn or fetal NK cells express CD57; however, the frequency of CD57-bearing NK cells increases with age. We assessed the transcriptional, phenotypic, and functional differences between CD57(+) and CD57(-) NK cells within the CD56(dim) mature NK subset. CD57(+) NK cells express a repertoire of NK-cell receptors, suggestive of a more mature phenotype, and proliferate less when stimulated with target cells and/or cytokines. By contrast, a higher frequency of CD57(+) NK cells produced interferon-γ and demonstrated more potent lytic activity when these cells were stimulated through the activating receptor CD16; however, they are less responsive to stimulation by interleukin-12 and interleukin-18. Finally, CD57 expression is induced on CD57(-)CD56(dim) NK cells after activation by interleukin-2. A combination of a mature phenotype, a higher cytotoxic capacity, a higher sensitivity to stimulation via CD16, with a decreased responsiveness to cytokines, and a decreased capacity to proliferate suggest that CD57(+) NK cells are highly mature and might be terminally differentiated.

Expression patterns of NKG2A, KIR, and CD57 define a process of CD56dim NK-cell differentiation uncoupled from NK-cell education

Natural killer (NK) cells are lymphocytes of the innate immune system that, following differentiation from CD56(bright) to CD56(dim) cells, have been thought to retain fixed functional and phenotypic properties throughout their lifespan. In contrast to this notion, we here show that CD56(dim) NK cells continue to differentiate. During this process, they lose expression of NKG2A, sequentially acquire inhibitory killer cell inhibitory immunoglobulin-like receptors and CD57, change their expression patterns of homing molecules, and display a gradual decline in proliferative capacity. All cellular intermediates of this process are represented in varying proportions at steady state and appear, over time, during the reconstitution of the immune system, as demonstrated in humanized mice and in patients undergoing hematopoietic stem cell transplantation. CD56(dim) NK-cell differentiation, and the associated functional imprint, occurs independently of NK-cell education by interactions with self-human leukocyte antigen class I ligands and is an essential part of the formation of human NK-cell repertoires.

Analysis of natural killer (NK) cell activity and adhesion molecules on NK cells from umbilical cord blood

The activity of natural killer (NK) cells in human umbilical cord blood (CB) has been reported to be low, compared with that in adult peripheral blood (PB) in vitro. To examine the cause of this, after dividing the CD56+/CD3- cells in CB and PB into CD56bright and CD56dim NK cells, the NK cell activities and the expression of various surface antigens were assayed for each fraction. The NK cell activity of CD56dim NK cells in CB was significantly lower than that in PB (P = 0.0003), whereas, there was no significant difference between the NK cell activity of CD56bright NK cells in PB and CB. The expression levels of adhesion molecules (CD2, CD11a, CD18, DNAX accessory molecule-1), CD16, and CD57 for CD56dim NK cells in CB were significantly lower than those in PB, and approximately one-third of CB CD56dim NK cells were capable of forming conjugates with K562 cells, compared with PB CD56dim NK cells. Furthermore, the inhibition of both the NK cell activities and binding of CD56dim NK cells in PB and CB by monoclonal antibody against each of these adhesion molecules suggests that they play an important role in NK cell activity. These findings show that the low NK cell activity in CB is caused by the low NK cell activity of CD56dim NK cells and that the low expression level of adhesion molecules on CB CD56dim NK cells may contribute to this low NK cell activity.

The effects of neurosurgical stress on peripheral lymphocyte subpopulations

STUDY OBJECTIVE

To observe changes in the peripheral lymphocyte subpopulations as an index of cellular immunity during neurosurgical procedures.

DESIGN

Clinical study.

SETTING

Operating room of a university hospital.

PATIENTS

11 patients with early intracranial disease who were scheduled to undergo elective neurosurgery with general anesthesia. Patients in the control group (n = 10) underwent minor surgeries such as ophthalmologic, otorhinolaryngological, or orthopedic surgeries.

INTERVENTIONS

Blood was sampled before anesthesia induction (t0) for baseline and at 1 hour (t(1)) and 2 hours (t(2)) following surgical incision.

MEASUREMENTS

Detection and quantification of lymphocyte subpopulations were performed at each time point using single-label and double-label analyses of monoclonal antibodies against lymphocyte membrane surface markers.

MAIN RESULTS

Significant changes in patients who underwent a neurosurgical procedure included: the percentage of total T cells (CD3+) from 57.54 +/- 3.50% at t(0) to 51.41 +/- 4.26% at t(1) and 46.29 +/- 4.02% at t(2); the percentage of inducer T cells (CD4+, Leu8+) from 27.39 +/- 2.26% at t(0), to 23.26 +/- 2.30% at t(1) and 20.82 +/- 2.70% at t(2); the CD4/CD8 ratio, from 1.78 +/- 0.25% at t(0) to 1.35 +/- 0.12% at t(1) and 1.22 +/- 0.17% at t(2). The percentage of suppressor T cells (CD8+, Leu15+) increased significantly from 10.8 +/- 1.07% at t(0) to 13.64 +/- 1.62% at t(1), and 14.82 +/- 1.24% at t(2). The percentages of the natural killer cell subsets also increased significantly. Control group patients who underwent minor surgeries showed no significant changes.

CONCLUSIONS

Neurosurgery-induced significant suppression of cellular immunity was demonstrated in peripheral lymphocyte subpopulations, probably from the surgical stress on the central nervous system.

Decrease of suppressor-inducer (CD4+ CD45RA) T lymphocytes and increase of serum immunoglobulin G due to perceived job stress in Japanese nuclear electric power plant workers

To clarify the effects of perceived job stress on the immune system, a cross-sectional study was conducted in 116 male Japanese workers of a nuclear electric power plant (age, 20 to 39; mean, 31 years). Perceived job stress, i.e., psychological job demand, job control, worksite social support, and job strain, was assessed by means of the Japanese version of the Job Content Questionnaire. The job strain score was calculated as the ratio of the job demand score to the job control score. Blood samples were taken from all workers, and numbers of T and natural killer cell subpopulations, B lymphocytes, total lymphocytes and white blood cells, and serum concentrations of immunoglobulins (IgG, IgM, IgA, IgE and IgD) in their blood were measured. The workers were divided into higher and lower strain groups according to their job strain scores. The number of CD4+ CD45RA+ T lymphocytes in the higher strain group having the job strain score of 0.5 or more (41 workers) was significantly smaller than that in the lower strain group having the score of less than 0.5 (75 workers). In contrast, the serum IgG concentration in the former group was significantly higher than that in the latter group (analysis of covariance with age and smoking as covariates). Also, the numbers of total CD4+ T and total T (CD3+) lymphocytes and of white blood cells in the former group were significantly smaller than those in the latter group. After controlling for age and smoking by the partial correlation coefficient in all 116 workers, the number of CD57+ CD16+ natural killer cells was inversely correlated with job demand and with job strain; the number of CD8+ T lymphocytes was positively correlated with worksite social support; and serum IgG and IgM concentrations were positively correlated with job strain. It is suggested that higher job strain decreases the number of CD4+ CD45RA+ T lymphocytes in male Japanese workers but increases serum IgG concentrations.

Adhesion defects of antibody-mediated target cell binding of neonatal natural killer cells

Neonates are unusually susceptible to herpes simplex virus infection, which may be explained in part by defects in killing of herpes simplex virus-infected cells by natural killer (NK) cell cytotoxicity and antibody-dependent cellular cytotoxicity. The mechanism for these defects remains poorly defined. We have for the first time used immunomagnetically enriched NK cells to explore neonatal NK cell phenotype and target cell adhesion. CD56-positive neonatal NK cells had markedly lower CD57 expression, but adult level expression of adhesive glycoproteins (CD18, CD44) and Fc receptor for IgG (CD16). Although the cells conjugated normally with target cells in the absence of antibody, antibody-mediated conjugation was significantly lower than that of NK cells from adults (p < 0.002). These results demonstrate intact adhesion in neonatal NK cell cytotoxicity. In contrast, defective neonatal antibody-dependent cellular cytotoxicity is caused, in part, by an adhesion defect in the presence of antibody.

Treatment of head and neck cancers with BRMs--prolongation of survival

It has been reported that immunologic function is deteriorated in head and neck cancer patients by primary therapies such as surgery, irradiation and chemotherapy or tumor itself. As previously described by us, immunologic dysfunction in such patients may be recovered by treatment with BRMs. In the present study, we investigated the effects of BRMs on survival of patients who had primarily been treated in our clinic. Fifty-one patients (23 patients; Stage I or Stage II, 28 patients; Stage III or Stage IV) were treated with BRMs (BRM group), and 49 patients (22 patients; Stage I or Stage II, 27 patients; Stage III or Stage IV) were employed as controls (Control group). The results obtained were as follows: (1) In patients of all Stages, the survival period was significantly (p < 0.05) longer in BRM group than in Control group; (2) The survival periods of patients of Stage I or Stage II were not different between the groups; and (3) The survival period of BRM group was significantly (p < 0.05) longer than that of Control group in patients of Stage III or Stage IV. There were observed more patients in BRM group who survived for a prolonged period. These results suggest that BRMs may be useful for recovering immunologic function in head and neck cancer patients particularly of Stage III or Stage IV who usually receive multimodality therapy.

Changes in T, B, and NK lymphocyte subsets during and after normal pregnancy

PROBLEM

Pregnancy affects the maternal immune system and the clinical course of maternal diseases. Here we report the changes in the detailed lymphocyte subsets of helper T cells, suppressor T cells, CD5+ B cells, T cell receptor (TCR) alpha beta-positive T cells (T alpha beta cells), TCR alpha beta-negative T cell (T gamma delta cells), and other during and after pregnancy through to one year postpartum, and discuss the significance of the changes.

METHOD

The absolute numbers of helper T cells, suppressor T cells, cytotoxic T cells, TCR alpha beta-negative T cells (T gamma delta cells), CD5- B cells, CD5+ B cells, and NK cell subsets were examined by two-color flow cytometry in peripheral blood from 51 healthy non-pregnant women, 106 healthy pregnant women, and 148 healthy postpartum women.

RESULTS

In early pregnancy, the numbers of suppressor T cells and NK cells with strong cytotoxicity (NK+3 cells) increased, and the number of cytotoxic T cells decreased. In late pregnancy, the helper T cell and NK+3 cell numbers decreased. T alpha beta, CD5- B and CD5+ B cells decreased during pregnancy. After delivery, helper T cells and cytotoxic T cells increased from 1 to 4 months postpartum, and suppressor T cells increased at 7 months postpartum. TCR alpha beta-negative T cells increased at 4 to 10 months postpartum. Both CD5- and CD5+ B cells decreased further at 1 month postpartum, but CD5+ B cells increased markedly at 7 to 10 months postpartum.

CONCLUSIONS

These data indicate that 1) early increases of suppressor T cells and NK+3 cells during pregnancy may be related to the mechanism to accept or reject the fetus in early pregnancy, respectively; 2) late decreases of helper T cells and NK+3 cells may be related to the maintenance of pregnancy: 3) postpartum increases of helper T cells, cytotoxic T cells, TCR alpha beta-negative T cells (T gamma delta cells), and CD5+ B cells may be related to the postpartum aggravation of autoimmune diseases; and 4) the immunological effects of pregnancy remains until about 1 year after delivery.

Rapid evolution of human immunodeficiency virus strains with increased replicative capacity during the seronegative window of primary infection

The relationship between host and virus was examined during the initial stages of human immunodeficiency virus type 1 (HIV) infection in a volunteer from the Multicenter AIDS Cohort Study (MACS). The individual was asymptomatic and unaware of his infection during an initial donation of blood and inguinal lymphoid tissue. Proviral DNA, however, was present in cells from both sources, HIV RNA was detected in the plasma, and CD4+ cell levels were reduced by approximately 50% compared with previous donations in the MACS. In a second blood donation 12 days later, plasma HIV RNA increased 200-fold in tandem with viral isolates with an increased growth phenotype in vitro. HIV burden was ultimately suppressed upon seroconversion and the emergence of HIV-specific CD8+ cytotoxic T lymphocytes. These observations provide further evidence that the potential benefits of early treatment may be maximized during the early stages of infection, when viral fitness may be low but is unopposed by immune responses.

Natural killer cells and cancer

BACKGROUND

Natural cytotoxicity, mediated by natural killer (NK) cells and cell with lymphokine-activated killer (LAK) activity, is believed to play an important role in host anti-cancer mechanisms.

METHODS

The authors critically review recent publications on the role of natural cytotoxicity in patients with cancer.

RESULTS

In patients with cancer, several studies have noted variations in the numbers and activity of NK and cells with LAK activity in different body compartments. NK cell activity in the peripheral blood lymphocytes (PBLs) is higher than that found in lymph nodes and within tumors, and this appears to be due to the presence of suppressor factors. The natural cytotoxicity of PBLs in patients with different types of cancers varies. However, there appears to be a trend for natural cytotoxicity to be reduced in certain cancer patients, possibly related to tumor volume or dissemination. Anti-cancer treatments (e.g., surgery, hormonal modulation, radiotherapy and chemotherapy) can also result in suppression of natural cytotoxicity, although the long-term effect on response to treatment and development of metastases is at present unknown.

CONCLUSIONS

NK and LAK cells, through the use of immune biologic modifiers, have been demonstrated to have a therapeutic role in the treatment of human cancers. Further studies are required to determine the optimal dosages and combinations of chemotherapeutic agents, the timing of surgery, and the adjuvant use of immune biologic response modifiers. An increasing awareness and understanding of this field, may allow for the future development of anti-cancer therapies.

Intrapair differences of the blood cell components and lymphocyte subsets in monozygotic and dizygotic twins

We evaluated the relative influence of genetic and environmental factors on leukocytes, lymphocytes, neutrophils, monocytes, erythrocytes, reticulocytes, hemoglobin, platelets, T lymphocyte subsets, and NK marker cells in monozygotic (MZ) and dizygotic (DZ) twins. Peripheral blood components were measured in 154 healthy twin pairs (118 MZ pairs and 36 DZ pairs) and lymphocyte subsets in 48 healthy twin pairs (38 MZ pairs and 10 DZ pairs). Platelets and erythrocytes showed higher intraclass correlations in the MZ pairs than in the DZ pairs in the males. However, in the females, the intraclass correlations for these components were similar between the MZ and DZ pairs. Neutrophils and monocytes showed low intraclass correlations in the MZ pairs. The absolute number of CD4+ cells and the CD4+/CD8+ cell ratio showed high intraclass correlations regardless of age in the MZ pairs in both males and females. The intraclass correlation for the absolute number of CD3+ cells was low in pairs aged > or = 60 years in the MZ pairs. The absolute numbers of CD16+ cells and CD56+ cells showed high intraclass correlations regardless of age in the MZ pairs.

Defective natural killer cell activity and deficient production of interferon-gamma in children with acute lymphoblastic leukemia

Natural killer (NK) cell activity, OK-432-augmented-NK cell activity, concentrations of interferon-gamma (IFN-gamma) in the culture supernatants of lymphocytes stimulated with OK-432, and subsets of NK cells and memory T cells were analyzed in 42 children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy. Natural killer and augmented-NK cell activities, and concentrations of IFN-gamma in the supernatants of cultured lymphocytes, were significantly lower in the patients with ALL than in age-matched control children. Among the NK cell subsets, proportions of CD57+ cells in the patients with ALL were significantly higher than in the controls, and proportions of a memory T cell subset (CD4+ CD29+ T cells) in the patients were also significantly higher than in the controls. These results suggest that the function of NK cells and memory T cells that are considered as IFN-gamma producing cells, may be defective in ALL, and that CD57+ cells and CD4+ CD29+ cells may be resistant to or recover rapidly from suppression by cytotoxic chemotherapy.

Functional and phenotypic assessment of neonatal human leucocytes expressing natural killer cell-associated antigens

A subpopulation of mononuclear leucocytes was prepared from umbilical cord venous blood by immunomagnetic depletion of lymphocytes and monocytes using monoclonal antibodies to CD2, CD3, CD14 and CD19 antigens, and examined for NK cell-associated phenotypic and functional properties. The depleted population was enriched for the NK markers CD16 (mean 53.6% positive) and CD56 (mean 42.7% positive). While there was considerable overlap of these two markers, approximately one-third of CD16+ cells were CD56-; in contrast, few CD56+ CD16- cells were found. CD16+/CD56+ cells also co-expressed CD7 and CD45RA antigens, while a minority weakly expressed CD8. Another marker of adult NK cells, CD57, was virtually absent from CD16+/CD56+ cells, as was MHC Class 2. Freshly depleted cord cells had virtually absent natural cytotoxicity to K562 targets in a chromium release assay, but NK activity could be induced after 18 h exposure to recombinant human IL-2, without significant change in phenotype. These findings confirm the phenotypic differences and functional defects of NK cells in cord blood as compared to adult blood, and identify a subset of cells with unique phenotype (CD2- CD3- CD7+ CD16+ CD56- CD57-). The precise relationship of this subset of cells to NK lineage remains to be defined.

Immunological investigation of adult patients with primary herpes simplex virus-1 infection

Peripheral blood mononuclear cell parameters were examined in 17 adult patients with primary herpes simplex virus-1 (HSV-1) infection. Two-color flow cytometry revealed an increase in HLA-DR+ T cell and Leu8+ T cell subsets, and a decrease in CD57+CD16+ subset in the patients. In the symptomatic phase of HSV-1 infection, serum interferon gamma (IFN-gamma) level increased in many patients, and the mean serum level in the patients (0.26 +/- 0.12 U/ml) was significantly higher than the mean control level (0.14 +/- 0.06 U/ml). Soluble intercellular adhesion molecule-1 (sICAM-1) in patients' serum also was increased to a mean level of 398 +/- 130 ng/ml at the first visit. Both the IFN-gamma and sICAM-1 levels fell to near the control levels after the disappearance of oral inflammation. Natural killer (NK) activity was at first increased (mean 46.1 +/- 17.9%), and later decreased to the control level (mean 38.4 +/- 10.6%). In contrast, lymphokine activated killer (LAK) activity at the first visit (mean 53.2 +/- 15.7%) was significantly lower than the control level (mean 69.5 +/- 10.3%). PHA- or ConA-stimulated lymphocytes from the patients incorporated less thymidine than control lymphocytes. These reduced lymphocyte reactivities recovered to the control levels after the disappearance of the acute infection. These results indicate some of the characteristics of lymphocyte pathophysiology in primary HSV-1 infection.

Distribution of natural killer cells in periodontal diseases: an immunohistochemical study

We studied the distribution and incidence of natural killer (NK) cells in gingiva affected with adult periodontitis (AP) and rapidly progressive periodontitis (RP) with immunohistochemical methods using antibodies Leu-7 and Leu-11b. The incidence of Leu-7 positive cells revealed no significant difference among mild AP, severe AP, and RP. On the other hand, Leu-11b positive cells were frequently found in severe AP and RP. The accumulation of NK cells reacting with Leu-11b in the infiltrated connective tissue was greater in severe forms of periodontal disease (severe AP and RP) than in mild AP. These results suggest that Leu-11b positive NK cells may play a role in the destruction of tissues in periodontal diseases.

Ontogeny of human natural killer (NK) cells: fetal NK cells mediate cytolytic function and express cytoplasmic CD3 epsilon,delta proteins

Natural killer (NK) cells have been defined as CD3 epsilon-, CD16+ and/or CD56+ lymphocytes that mediate major histocompatibility complex (MHC)-unrestricted cytotoxicity against certain tumors and virus- infected cells. Unlike T lymphocytes, NK cells do not rearrange or productively express T cell antigen receptor genes. Moreover, NK cells from adults have been reported to not express CD3 gamma, delta, or epsilon proteins on the cell surface or in the cytoplasm. Nonetheless, NK cells have been shown to share a number of antigenic and functional similarities to T cells that suggest the possibility of common origins. In this report, we demonstrate that functional NK cells exist in liver at early stages of human embryonic development. Freshly isolated fetal NK cells mediated MHC-unrestricted cytotoxicity against NK-sensitive targets and acquired the ability to lyse NK-resistant tumors after overnight culture in interleukin 2. Unlike adult NK cells, freshly isolated fetal liver NK cells and clones derived from these cells, as well as a subset of cord blood NK cells, express substantial levels of CD3 delta and CD3 epsilon proteins in the cytoplasm. Expression of CD3 epsilon and CD3 delta transcripts and cytoplasmic proteins in fetal NK clones was confirmed by polymerase chain reaction and Western blot analysis. These findings support the concept that NK and T cells may arise from a common progenitor that expresses components of the CD3 complex. Alternatively, it is possible that the cytoplasmic CD3 delta, epsilon+ fetal NK cells represent a distinct subpopulation of NK cells that is predominant in the fetus, but replaced by the cytoplasmic CD3 delta,epsilon- adult NK cell population after embryogenesis.

Felty's and pseudo-Felty's syndromes

Felty's syndrome, consisting of rheumatoid arthritis, leukopenia, and splenomegaly, has been recognized as a distinct clinical entity for more than 60 years. Clinical and laboratory manifestations of the condition are reviewed. The major sources of morbidity and mortality remain recurrent local and systemic infections. Immunogenetic analysis shows a strong association with HLA-DR4, in addition to DQ beta 3b and C4B null allele. Potential mechanisms of neutropenia are contrasted, including impaired granulopoiesis and neutrophil-immune complex interactions. Lithium carbonate and splenectomy may have a role in the treatment of fulminant disease. Maintenance therapy should be directed at control of the underlying inflammatory arthropathy. A syndrome of proliferation of large granular lymphocytes and neutropenia, associated with rheumatoid arthritis in 23% to 39% of cases, has been described recently. Cases of "pseudo-Felty's" syndrome are often confused with traditional Felty's syndrome, which has twice the prevalence. The clinical and laboratory distinctions between these two conditions are elaborated.

Two different maturational stages of natural killer lymphocytes in human newborn infants

The objective of this study was to assess the basis for the diminished natural killer (NK) lymphocyte activity of neonates. We found either severely reduced (63% of 68 neonates) or normal (similar to healthy adult) levels of NK activity. The percentages of cord blood mononuclear cells from the two groups of infants that expressed CD16, a differentiation antigen found in NK cells, were similar and within the range found in peripheral blood mononuclear cells of adults. However, infants with low NK activity had reduced numbers of cells in the CD16+56+ subpopulation, whereas the number of these effector cells present in cord blood mononuclear cells from infants with normal NK activity was within the range found in adults. Recombinant interleukin-2, but not recombinant interferon-gamma, normalized the low NK activity of infants in a dose- and time-dependent manner. Analysis of the pattern of target cell susceptibility to lysis, together with the CD16+CD3- phenotype of the precursor and effector lymphocytes, demonstrated that the induced cytotoxicity was mediated by NK cells. In contrast, NK cells from infants with normal cytotoxic levels exhibited a functional response to interleukin-2 and interferon-gamma similar to that of adults. Our results indicate that NK cells in human neonates go through two different maturational stages.

Clonally expanded CD3+, CD4-, CD8- cells bearing the alpha/beta or the gamma/delta T-cell receptor in patients with the lymphoproliferative disease of granular lymphocytes

Among 60 retrospectively assessed patients with the lymphoproliferative disease of granular lymphocytes (LDGL), lymphocytes from only 2 patients had the CD3+, CD4-, CD8- phenotype, rarely observed in normal peripheral blood lymphocytes (about 3%). In this paper we report a detailed study of lymphocytes isolated from these two patients. The cells from patients 1 had the CD3+, CD4-, CD8-, WT31-, beta F1-, TCR delta 1+, Ti gamma A-, BB3+, CD7+, CD16-, CD57+ phenotype, while cells from patient 2 had a phenotype even more rarely observed on normal lymphocytes: CD3+, CD4-, CD8-, WT31+, beta F1+, TCR delta 1-, CD7+, CD16-, CD57+. Thus, in only the first case the cells expressed the gamma/delta T-cell receptor (TCR) on the membrane, while the cells from the second case had the alpha/beta TCR. Genetic studies showed that in case 1 the TCR gamma gene was rearranged and the beta chain gene configuration was germline; the TCR mRNA was of normal size for the gamma chain, while that of the beta chain was truncated. Case 2 had the beta and the gamma genes of the TCR rearranged, but only the alpha and beta mRNA were expressed. In agreement with these findings, the delta chain gene of the TCR was rearranged in case 1 and was deleted in case 2. Cytotoxic activity was absent in cells from case 1 and low in case 2; in the latter, the lytic activity could be up-regulated following incubation with IL-2 or an anti-CD3 monoclonal antibody. Our study indicates that CD3+, CD4-, CD8- lymphocytes are rarely expanded in patients with LDGL. The detection of a lymphoproliferative disease of a CD3+, CD4-, CD8-, alpha/beta + cell may contribute to a better characterization of this novel lymphocytic subpopulation.

Lymphocyte subset reference ranges in adult Caucasians

We report here the distributions of lymphocyte populations bearing the following antigens: CD3 (T cells), CD19 (B cells), CD4 (T helper/inducer cells), CD8 (T suppressor/cytotoxic and some NK cells), and CD3-, CD16+, and/or CD56+ (NK cells). At four sites, analyses were performed on healthy, normal subjects between the ages of 18 and 70, using identical flow cytometry systems and techniques. Reference ranges (unadjusted for sex differences and age variation) are CD3 (61 to 85%), CD19 (7 to 23%), NK (6 to 29%), CD4 (28 to 58%), and CD8 (19 to 48%). The lymphocyte subpopulation distributions for all antigens were found to be similar at all sites. By combining data from all sites, it has been possible to estimate age variation and sex differences for each of these subpopulations. Age and sex associated differences are substantial for some lymphocyte subsets (CD3, CD4, NK cells), and proper accounting of these effects is essential in evaluating the individual patient, if further disease-related variation is to be accurately and consistently assessed. It appears possible to recommend reference ranges for lymphocyte population parameters applicable across national and laboratory boundaries. These ranges provide a basis for comparing results from different institutions and for combining such results on subjects and patients from several institutions, provided the methodology and equipment are identical at all sites.

Identification of activated T cell receptor gamma delta lymphocytes in the liver of tumor-bearing hosts

T cell receptor (TcR)gamma delta cells are known to be a minor population of T lymphocytes in the blood (less than 10%) and other peripheral lymphoid organs in healthy donors. We demonstrated here that a large proportion of TcR gamma delta cells, i.e., up to 30% of mononuclear cells (MNC) were detectable in the liver, but not other lymphoid organs of cancer patients. More importantly, the majority of such TcR gamma delta cells (greater than 70%) were shown to be lymphoblastic by electron microscopy. An activation marker of T lymphocytes, Leu-19 (CD56) was also highly expressed on the hepatic TcR gamma delta cells. The possibility of hepatic TcR gamma delta cells being activated was further examined in mice. C3H/He mice injected with syngeneic tumor cells were demonstrated to have an increased number of liver MNC; such MNC showed an ability to proliferate in vitro. These mice eventually had a considerable proportion of TcR gamma delta cells in the liver, showing activation markers, the Ia and LFA-1 antigens. These results suggest that the liver may be an important organ for activation and probably expansion of TcR gamma delta cells especially in tumor bearing hosts.

Morphometric evaluation of CD16-positive cells with respect to CD2 antigen coexpression

We examined morphometric as well as functional characteristics of CD16-positive human peripheral blood lymphocytes on the basis of the coexpression of the CD2 antigen. For morphometric analyses, nuclear area and cellular area were determined by counting line cross-points of a superimposed quadratic lattice test system overlying nuclei and the whole cell, respectively. Moreover, to evaluate the cellular villousity degree, the maximum inscrible circle and an irregular polygon were inscribed within cell profiles. The cytoplasm fraction included between the plasmalemma and the traced irregular polygon was considered as the villous portion of the cell. Finally, the NK capability was measured in a 6-hr 51Cr-release assay with human K-562 myeloid cells as targets. Within the CD16-positive cell population, the CD16-positive/CD2-negative cells seem to represent the most efficient NK cell subset. To the higher NK capability correspond a higher villousity degree and a lower nuclear area/cellular area ratio of the CD2-negative/CD16-positive subset, when compared with CD2-positive/CD16-positive cells.

Clinical significance of natural killer activity in patients with transitional cell carcinoma of the bladder

We studied the relationship of natural killer activity from peripheral blood mononuclear cells with clinical stage of disease and the different modalities of treatment in 67 untreated patients with transitional cell carcinoma of the bladder and 29 normal controls. Peripheral blood mononuclear cells from 39 patients with superficial bladder tumor (stages Ta and T1) showed a natural killer cell activity similar to that of controls (p greater than 0.05), while in 28 patients with infiltrating tumors (stages T2, T3 and T4) this activity was significantly depressed (p less than 0.01). This functional phenomenon cannot be ascribed to a deficient number of natural killer cells in patients with infiltrating tumors, since the amounts of HNK-1+ (Leu 7), CD16+ (Leu 11) and CD11b+ (OKM1) cells in peripheral blood mononuclear cells were similar in the 3 groups of subjects (p greater than 0.05). Furthermore, the natural killer activity of peripheral blood mononuclear cells was normal (p greater than 0.05) in patients who underwent transurethral resection of the tumors and intracavitary cytostatic therapy with doxorubicin who remained free of disease at least 6 months after treatment. However, in patients with superficial recurrent tumor a significant decrease in the natural killer activity of peripheral blood mononuclear cells was observed (p less than 0.05), which was more pronounced in those with infiltrating recurrence. Also, in the latter patients total cystoprostatectomy was associated with a relevant increase in the spontaneous level of peripheral blood mononuclear cells. We conclude that in patients with transitional cell carcinoma of the bladder there is a correlation of the levels of natural killer activity in peripheral blood mononuclear cells with clinical evolution and pathological stage of disease. The determination of this activity is useful to monitor patients with transitional cell carcinoma of the bladder.

Natural killer cytotoxicity in the diagnosis of immune dysfunction: criteria for a reproducible assay

Current evidence indicates that natural killer (NK) cells, which are large granular lymphocytes that mediate non-major histocompatibility complex (MHC)-restricted cytotoxicity and antibody-dependent cytotoxicity and that are involved in multiple regulatory, developmental, and immunologic processes, are important in health. Immunodeficiency states presenting with low NK activity are often associated with malignancies, chronic viral infections, or autoimmune diseases. Monitoring of NK function appears to be indicated as an aid to diagnosis, prognosis, and follow-up after therapy. Reliable performance of NK assays in a clinical laboratory requires that uniform criteria be established and followed for the acceptability of results. Statistical analysis of daily variability can be of great assistance in identifying and tracking sources of error, but routine statistical adjustments are not generally advisable. The quality control program described here provides a degree of assurance that this cytotoxicity assay can be dependable whether performed at one time point or serially. The successful implementation of this program requires laboratory resources, biostatistical support, and interpretative skills, all of which are available in a modern clinical laboratory.

[Flow cytometry in immunology and hematology: some essential practical aspects]

Flow cytometry, supported by monoclonal antibodies, has widely contributed in the cellular identification, notably in the clinical and haematological fields. This technique has found several applications since the qualitative phenotyping and the quantitative analysis of the immune system's cell populations are helpful in the diagnosis and the therapy. Besides, these indications require an appropriate knowledge of several methodological aspects including factors related to the sample donor: age and sex; sampling: time and quantity; and the sample preparation conditions. References values, needed for the results interpretation, have a meaning only if they are defined within these validity limits. Previous trials have been done in order to define a biological value representative of the immunological status, such as the CD4/CD8 ratio. Unfortunately this ratio is not justified in the scope of new knowledge concerning the cellular interactions and the functional heterogeneity of cells involved in the immune system.

Large granular lymphocytes from B-chronic lymphocytic leukemia patients inhibit normal B cell proliferation

Large granular lymphocytes (LGL) may exert regulatory influences on B cell immunoglobulin synthesis. We, therefore, investigated the influence of LGL from controls and B cell chronic lymphocytic leukemia patients (B-CLL) on control B cell proliferation to costimulation with the F(ab')2 fragment of goat antihuman mu and B cell growth factor (BCGF). Purified LGL (greater than 90% by morphology) from control and B-CLL peripheral blood were added in various concentrations to purified control B cells and incubated with anti-mu and BCGF for 3 days. [3H]-thymidine uptake of B cells was then measured. There was no proliferation of control or CLL LGL alone to the costimulatory signals of the F(ab')2 fragments of goat antihuman mu chain and BCGF. Addition of control LGL to equal numbers of control B cells did not blunt control B cell responsiveness to BCGF (with control LGL 8,649 +/- 298 cpm vs. control B cells alone 8,336 +/- 556 cpm, mean +/- SEM). When control LGL were increased to 10:1 LGL:B cell ratio, the maximal inhibition by control LGL of control B cell proliferative response to BCGF was 23%. In contrast, addition of CLL LGL at a 1:1 LGL:B cell ratio resulted in marked impairment of the control B cell proliferative response to BCGF (with CLL LGL 3,586 +/- 954 cpm vs. control B cells alone 8,649 +/- 298 cpm). Inhibition by CLL LGL occurred in a cell-concentration-dependent manner. No difference in CLL LGL's inhibitory effect on either resting or activated control B cell responsiveness to BCGF was noted. Inhibition of de novo protein synthesis (by cycloheximide inhibition) of CLL LGL did impair CLL LGL's inhibitory capacity for BCGF-induced B cell proliferation. A possible explanation for these findings includes the possibility that a subgroup of LGL with B cell suppressive activity may have expanded as a host response to the B cell leukemia or as part of the disordered cell regulation in B-CLL.

Cytotoxic effector cells of the immune system

The organism contains several types of cytotoxic cells which are able to lyse host and foreign cells. Cytotoxic T-lymphocytes (CTL) appear to play the most important role among the killer cells but other lymphatic cells, such as natural killer (NK) cells and lymphokine-activated killer (LAK) cells as well as macrophages are also highly effective in the lysis of appropriate targets. The various cytotoxic effector cells differ distinctly concerning origin, phenotype, morphology and target cell specificity, but they bear the common feature that they destroy the target cells in a contact-dependent non-phagocytotic process. CTL are characterized by typical lysosomal granules and by the expression of a characteristic pattern of surface molecules. They recognize specific antigens which are presented in context with molecules of class I major histocompatibility complex (MHC). NK cells, on the other hand, kill the appropriate targets without prior immunisation and without requiring recognition of MHC molecules at the target cells. They also bear a typical pattern of surface markers which differ in several aspects from that of CTL. Human NK cells are further characterized by peculiar cytoplasmic granules with parallel tubular arrays which are not present in other cytotoxic cells. LAK cells constitute an additional, only recently described, killer cell population which arise from lymphatic cells in the presence of interleukin-2. They appear to represent a functional unique cytotoxic effector cell system with an exceptionally wide target cell spectrum including normal and malignant cells of different origin. LAK cells, however, show a profound heterogeneity concerning the expression of phenotype surface markers and it is not yet clear whether they are a unique cell line. By electron microscopy they display peculiar intranuclear inclusion bodies which may be associated with prolonged stimulation by interleukin-2. CTL, NK and LAK cells appear to possess similar mechanisms for cytolysis including secretion of pore-forming proteins, serine proteases and other proteins. Furthermore, they are able to trigger the cleavage of DNA in the target cell nucleus by a hitherto unknown pathway. Macrophages differ substantially from other cytotoxic effector cells concerning morphology, phenotype, kinetic of activation and target cell spectrum. They perform a variety of functions whereby contact-dependent target cell lysis represents only one of their properties. After target cell binding they release over 20 different molecules such as interleukin-1 and tumor necrosis-factor-alpha as mediators for cytolysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Phenotypical and functional heterogeneity of the large granular lymphocytes increased after various treatments in a patient with combined immunodeficiency

A boy with combined immunodeficiency having low natural killer (NK)-cell activity received thymopoietin pentapeptide (TP-5) treatment, transplanted with T cell-depleted HLA-haploidentical bone marrow (BMT) cells from his father and with thymus tissue from an infant at different times during the first year of life. He showed a marked increase in large granular lymphocytes (LGL) both during the treatment with TP-5 and after BMT. The LGL generated following TP-5 injection had a T3+Leu11- surface phenotype and low NK activity. In contrast, the LGL appearing after BMT showed T3-, Leu7+, and/or Leu11+ surface phenotypes, had high NK- and K-cell activities, and were lymphokine-activated killer (LAK)-cell precursors. These killer activities were assigned to the Leu7-Leu11+ subset and proved to be of recipient origin. LGL proliferation following BMT was accompanied by neutropenia, which was improved in association with a reduction in the number of LGL and the appearance of T cells of BMT donor origin following thymus transplantation. This suggested the inhibition of granulopoiesis by the LGL and an in vitro study revealed that the Leu7+Leu11- subset of LGL suppressed the growth of granulocyte/macrophage colony-forming units. These results indicated that phenotypically different LGL could be generated by different treatments and that the LGL showing NK activity were distinct from those regulating granulopoiesis. It was also suggested that the generation of LGL was controlled by T cells.

Correlation between cytomegalovirus and toxoplasma gondii serology and lymphocyte phenotypes in peripheral blood and cord blood

Increased numbers of peripheral blood HNK1+ lymphocytes have been reported in transplant recipients, hemophilia patients treated with clotting factor concentrates, and HIV carriers. Our previous work has revealed a significant effect of cytomegalovirus (CMV) carrier status on HNK1+ lymphocytes. Since other antigenic stimuli may be also involved, we compared the effects of Toxoplasma gondii and CMV carrier status on lymphocyte subsets as defined by the CD3 and HNK1 markers in 288 healthy individuals. In contrast to CMV, T gondii carrier status had no significant effects on the CD3+, HNK1+ and CD3-, HNK1+ lymphocyte subsets. That result may be explained by the different relationships between these 2 microorganisms and their hosts. We also studied the effect of maternal CMV carrier status on the HNK1 expression by their offsprings' cord blood lymphocytes. None of the 100 newborns studied had serological evidence of congenital CMV infection. There were only few HNK1+ lymphocytes in the cord bloods, of which the majority was CD3-, and their proportions were not significantly influenced by maternal CMV carrier status. Since there has been probably no direct contact between maternal CMV and the newborns' immune systems, we suggest that the effect of CMV on the HNK1+ lymphocytes of its carriers, results from a direct interaction between virus or virus-infected cells and the immune system.

Biology of natural killer cells

Studies of cytotoxicity by human lymphocytes revealed not only that both allogeneic and syngeneic tumor cells were lysed in a non-MHC-restricted fashion, but also that lymphocytes from normal donors were often cytotoxic. Lymphocytes from any healthy donor, as well as peripheral blood and spleen lymphocytes from several experimental animals, in the absence of known or deliberate sensitization, were found to be spontaneously cytotoxic in vitro for some normal fresh cells, most cultured cell lines, immature hematopoietic cells, and tumor cells. This type of nonadaptive, non-MHC-restricted cellmediated cytotoxicity was defined as “natural” cytotoxicity, and the effector cells mediating natural cytotoxicity were functionally defined as natural killer (NK) cells. The existence of NK cells has prompted a reinterpretation of both the studies of specific cytotoxicity against spontaneous human tumors and the theory of immune surveillance, at least in its most restrictive interpretation. Unlike cytotoxic T cells, NK cells cannot be demonstrated to have clonally distributed specificity, restriction for MHC products at the target cell surface, or immunological memory. NK cells cannot yet be formally assigned to a single lineage based on the definitive identification of a stem cell, a distinct anatomical location of maturation, or unique genotypic rearrangements.

Comparison of NK-cell (Leu-7+ and Leu-11b+) populations in clinically healthy gingiva, chronic gingivitis and chronic adult periodontitis

Various investigations have reported the presence of cytotoxic lymphocyte activity in inflammatory periodontal disease. The collective evidence indicates that the inflammatory infiltrates of gingivitis and periodontitis should feature a major component of large granular lymphocytes (NK-cells) possessing cytotoxic potential. Thus, the purpose of this study was to determine and compare, by use of immunohistochemical methods, the numbers of NK-cells in biopsies of clinically healthy gingiva, chronic gingivitis and chronic adult periodontitis and their relationship, if any, to the T- and B-lymphocyte populations. Gingival biopsies were obtained from 8 patients in each of three disease groups selected on the basis of predetermined clinical criteria. Using the avidin-biotin immunoperoxidase technique, four consecutive serial sections from each biopsy specimen were stained with a panel of antihuman monoclonal antibodies for T-lymphocytes (UCHL-1) B-lymphocytes (CD-45R), and NK-cells (Leu-7 and Leu-11b). Analyses of variance yielded a statistically significant main effect for each cell immunophenotype. The Newman-Keuls Sequential Range Test showed statistically significant differences for all but two mean comparisons (p less than 0.01). The comparisons for UCHL-1 and Leu-7 between chronic gingivitis and periodontitis specimens did not demonstrate significance. Although T- and B-lymphocyte populations increased approximately 20 x progressing from healthy to gingivitis to periodontitis specimens, the NK-cell population showed only a 3 x increase which represented 19%, 6.6% and 7% of the total of all positively stained lymphocytes across biopsy groups.

Fulminant clonal expansion of large granular lymphocytes. Characterization of their morphology, phenotype, genotype, and function

A 39-year-old woman exhibited abrupt malignant transformation of the large granular lymphocytes (LGL) after a chronic course of T gamma-lymphoproliferative disease (T gamma-LPD). The T gamma-lymphocytes were CD2+, CD3-, CD8-, CD16+, Leu7-, and Leu19+ with morphologic characteristics of LGL. Newly appearing LGL were much larger and had more prominent azurophilic granules. Although fundamentally they had the same phenotype as the LGL in chronic stage, they showed increased Ia-like antigen and decreased CD16 antigen expressions. Immunoglobulin (Ig) G-kappa type monoclonal component was detected in the patient's serum. The LGL showed a germ-line configuration for T-cell receptor (TCR) beta and gamma chain genes, whereas the clonal chromosomal abnormalities indicated the neoplastic nature of the LGL. The LGL exhibited competent natural killer (NK), interleukin 2 (IL2) activated killer (AK), and antibody-dependent cell-mediated cytotoxicity (ADCC) activities. The LGL may have derived from NK cells at their mature stage with prethymic phenotype and may have influenced the homeostasis of the patient's humoral immune response.

Effect of smoking on natural killer cell activity in the lung

We investigated the effect of smoking on natural killer (NK) cell activity and distribution in bronchoalveolar lavage fluid (BALF) and blood. Initially, BALF NK cell activity was lower than the blood NK cell activity both in non-smokers (NS) and smokers (S). Following 24 hour culture, NK cell activity markedly increased in NS but not in S. Percentage distribution of Leu-7+ cells and Leu-11+ cells in BALF was similar in NS and S. But the BALF NK cell activity was significantly augmented by IL-2 or OK-432 (a streptococcal preparation) in NS. It appears that smoking reduces NK cell activity in BALF. It is conceivable that the low NK cell activity in BALF in S might contribute to increased incidence of infection and malignancy in smokers.