NKG2D in NK and T Cell-Mediated Immunity

One of the best characterized NK cell receptors is NKG2D, a highly conserved C-type lectin-like membrane glycoprotein expressed on essentially all NK cells, as well as on γδ-TcR⁺ T cells and αβ-TcR⁺ CD8⁺ T cells, in humans and mice. Here we review recent studies implicating NKG2D in T cell and NK cell-mediated immunity to viruses and tumors, and its potential role in autoimmune diseases and allogeneic bone marrow transplantation.     

Cell-Mediated Immunity in Allopurinol-Induced Hypersensitivity

Allopurinol may induce severe hypersensitivity characterized by hepatitis, interstitial nephritis, and skin rash. The mechanisms for this hypersensitivity syndrome are incompletely elucidated. Immunologic studies were performed on tissue and peripheral blood lymphocytes from a patient with allopurinol hypersensitivity. Immunohistochemistry was performed on sections of the liver biopsy utilizing monoclonal antibodies for T and B lymphocytes. Peripheral blood lymphocyte immunophenotyping by flow cytometry and peripheral blood lymphocyte stimulation studies with either allopurinol or oxypurinol measured as tritiated thymidine uptake were performed in the hypersensitive patient and compared to a group of six patients treated with allopurinol without hypersensitivity and eight normal control patients. Additional single- and dual-color immunophenotyping by flow cytometry of oxypurinol-stimulated lymphocytes was performed in the hypersensitive patient and compared to normal controls. The liver biopsy demonstrated predominantly a T lymphocyte infiltrate. The number of peripheral blood lymphocytes expressing activation antigens was significantly greater in the hypersensitive patient compared to that of both control groups. Lymphocytes from the hypersensitive patient were moderately stimulated by allopurinol and markedly stimulated by oxypurinol compared to both control groups. Oxypurinol-stimulated lymphocytes from the hypersensitive patient demonstrated enhanced expression of activation antigens compared to unstimulated lymphocytes from this patient and normal controls. These studies suggest that cell-mediated immunity directed toward allopurinol and more importantly to its oxypurinol metabolite is involved in the pathogenesis of allopurinol-induced hypersensitivity.     

Cell-Mediated Immunity in Diabetes Mellitus

Cell-mediated immunity was evaluated in patients with diabetes mellitus by delayed hypersensitivity skin tests and in vitro lymphocyte transformations. Only 44% of diabetic patients had skin test reactivity to Candida antigen, compared with 88% of normal controls (P < 0.001). Insulin-dependent diabetic (IDD) patients had abnormally low lymphocyte transformation responses to phytohemagglutinin, concanavalin A, and streptokinase-streptodornase (P < 0.05). This defect was not corrected by culturing the cells in nondiabetic plasma. IDD patients with persistent hyperglycemia (fasting serum glucose level, >200 mg/dl) had lower levels of transformation than did IDD patients with fasting serum glucose levels less than 150 mg/dl. Lymphocytes from two IDD patients with poor lymphocyte transformation responses had marked improvement in response to phytohemagglutinin when the lymphocytes were cultured after a preincubation period designed to deplete cultures of suppressor activity. Seven IDD patients were studied serially over 12 months. Lymphocyte transformation responses in four of these patients improved coincidentally with a change in the level of fasting hyperglycemia from >200 to <150 mg/dl. The other three IDD patients with consistent fasting serum glucose levels of >200 mg/dl had poor lymphocyte transformation responses. Diabetic patients have demonstrable defects in lymphocyte function which improved in a small number of patients with reduction in the level of fasting hyperglycemia.     

再生障碍性贫血患者细胞免疫指标的观察

采用酶免疫和放射免疫法分析了再生障碍性贫血(AA)患者外周血T淋巴细胞亚群、血清肿瘤坏死因子(TNF)、γ-干扰素(IFN-γ)和IL-2水平,以及患者外周血单个核细胞体外诱生的上述细胞因子水平。结果表明:患者CD4/CD8细胞比值降低或倒置(P<0.001),血清TNF和IFN-γ水平显著增高(P<0.01),外周血单个核细胞诱生的TNF、IFN-γ和IL-2水平均明显高于正常对照(P<0.01)。提示T淋巴细胞亚群比例失调和TNF、IFN-γ等造血负调控因子的过量分泌可能与AA的发病机制有关。     

Suppressed Cell-Mediated Immunity and Monocyte and Natural Killer Cell Activity Following Allogeneic Immunization of Women with Spontaneous Recurrent Abortion

Spontaneous recurrent abortion (SRA) has been treated by means of immunization with paternal or third-party white blood cells, yet the immunological basis for SRA and for the role of immunization protocols in pregnancy outcome remains controversial. To elucidate this question, nine women with SRA were immunized with paternal mononuclear cells and studied before and 2 weeks after immunization. Seven women who became pregnant gave birth to live newborns. Secretion of the T helper 1 cytokines IL-2 and interferon- by patients' mononuclear cells decreased, while production of IL-10 increased. The levels of natural killer and lymphokine-activated killer cell-mediated cytotoxicity were markedly decreased. Monocyte functions such as secretion of IL-l, tumor necrosis factor a, IL-6, and cytotoxic activity decreased concurrently with elevations in IL-10 and transforming growth factor secretion. Production of IL-12, a pivotal regulatory cytokine, decreased. Furthermore, B7/1 expression on patients' mononuclear cells was downregulated. This resulted in a decrease in monocyte costimulatory activity of purified T cells with soluble anti-CD3, paralleled by a decline in allogeneic proliferative responses. These results suggest that the improved pregnancy success rate in women with SRA following immunization may be partly related to suppression of cell-mediated immunity and monocyte and natural killer cell activity.     

Cell-Mediated Immunity to Cytomegalovirus in Pregnant Women

ABSTRACT: Employing the techniques of in vitro lymphocyte transformation (LTF) and complement fixation, cell-mediated immunity (CMI) and antibody to cytomegalovirus (CMV) were studied in pregnant and nonpregnant women. The LTF activity was determined by the whole blood microassay using four strains of CMV (AD-169 and its early antigen [EA], Davis, Veca, and Towne strains), and phytohemagglutinin (PHA). Lymphocyte transformation response to specific CMV antigens at 11–30 weeks of gestation and to nonspecific mitogen (PHA) in all pregnant and postpartum women were found to be significanty depressed compared with the nonpregnant women. The lower LTF responses to CMV antigen and PHA were found in specimens taken from pregnant women at 21–30 weeks of gestation. There were no significant differences in the mean complement-fixing (CF) antibody titers and the percentage of E-rosette-forming T lymphocytes between subjects in various stages of pregnancy. In addition, concanavalin A (Con A)-generated suppressor T cell activity was evaluated in pregnant and nonpregnant women. The suppressor effect of Con A-activated lymphocytes in pregnant women was somewhat higher than in nonpregnant women. These observations suggest that CMV-specific suppression of cellular immunity may play an important role in reactivation of CMV in pregnancy.     

Macrophages as Effectors of Cell-Mediated Immunity

Abstract

Recent molecular methodologies have demonstrated a complex microbial ecosystem in cystic fibrosis (CF) airways, with a wide array of uncommon microorganisms co-existing with the traditional pathogens. Although there are lines of evidence supporting the contribution of some of those emergent species for lung disease chronicity, clinical significance remains uncertain for most cases. A possible contribution for disease is likely to be related with the dynamic interactions established between microorganisms within the microbial community and with the host. If this is the case, management of CF will only be successful upon suitable and exhaustive modulation of such mixed ecological processes, which will also be useful to predict the effects of new therapeutic interventions.     

Alloimmune and autoimmune background in recurrent pregnancy loss - successful immunotherapy by intravenous immunoglobulin

PROBLEM: Immunotherapies [leukocyte immunization, intravenous immunoglobulin (IVIG)] introduced to treat women with recurrent spontaneous abortions (RSA) have still controversial results in most clinical trials. A selection of these patients would be advantageous for higher efficacy. METHOD OF STUDY: A complex immunological panel assay was offered to patients with reproductive failure without any other known cause. We focused here on the cellular immunological parameters. RESULTS: High cytotoxic T lymphocyte precursor frequency and cell-mediated cytotoxic activity and a rather high natural killer cell activity were found in alloimmune RSA patients. Thirty-two patients were investigated by immunological assays and in 78% of the women an alloimmune background could be defined. The efficacy of IVIG treatment was 96% in this group. CONCLUSIONS: The novel cellular immunological assays proved to be favourable for the indication of RSA patients and showed the usefulness of this selection process for effective immunotherapy.     

Suppression of Cell-Mediated Immunity in Experimental African Trypanosomiasis

Adult New Zealand white rabbits were experimentally infected with a parasitic African hemoflagellate, Trypanosoma congolense, and were subsequently tested for in vivo and in vitro aspects of cell-mediated immune function. Chronically infected rabbits were sensitized to mycobacterial protein and skin-tested with purified protein derivative; all infected animals demonstrated much milder skin-test responses to antigen than control groups. Similarly, peripheral blood lymphocyte responses in vitro to purified protein derivative and, as well, to phytohemagglutinin were markedly suppressed. Supernatant fluids of antigen-stimulated lymph node cell cultures from T. congolense-infected rabbits failed to demonstrate migration inhibitory factor activity but did possess normal levels of blastogenic factor activity. An active infection was necessary for demonstration of suppressed immune responses, and components present in infected rabbit serum were apparently not responsible for the observed abnormalities. Suppression of T-lymphocyte subpopulations may well explain the occurrence of numerous immunological aberrations arising during human and animal infections with the African trypanosomes.     

Evidence for Normal Cell-Mediated Immunity in Scrapie-Infected Mice

Comparisons between mixed lymphocyte cultures of splenocytes from scrapie-infected and normal mouse brain-inoculated control mice did not reveal any evidence of an impaired cell-mediated immune response in scrapie-infected mice. Likewise, mixed lymphocyte cultures of splenocytes from scrapie-infected and normal mice demonstrated that infected spleen cells had no scrapie-specific antigens on their surfaces. These data suggested that the absence of a detectable scrapie-specific immune response in infected mice was the result of an absence of an exposed scrapie-specific antigen and not due to any direct effect on the immune system.     

Regulatory Mechanisms of Cell-Mediated Immunity in Allogeneic Pregnancy

ABSTRACT: The transfer of cells from allopregnant animals to syngeneic receivers allografted with paternal strain tumor leads to mild but significant enhancement. The effect can be defined as T cell mediated. Cells from allopregnant animals can suppress a mixed lymphocyte reaction (MLR) of maternal responders against paternal stimulators. The effect relies upon a THY 1+, Ly 2+, Ia+ cell. Cell-mediated lympholysis (CML) assay could also be suppressed by cells from allopregnant animals. Placental products are capable of interfering with allograft rejection in vivo. They can block MLR in vitro, and seem to act in part via the induction of suppressor cells. The respective roles of these depressive components, together with enhancing antibodies, is discussed.     

In Vitro Cell-Mediated and Complement-Mediated Cytotoxicity to Murine Testicular Cells

ABSTRACT: Male BALB/c mice at 8 to 14 weeks of age were divided into three groups: group 1 was immunized with an emulsion of testicular cells (TCs) (10⁷/mouse), complete Freund's adjuvant (CFA), and extract of Bordetella pertussis (BP); group 2 was given CFA and BP injections; and group 3 was given sterile saline injections. Suspensions of TCs and spleen cells (SCs) from each mouse were prepared 4 weeks after the first immunization for a cytotoxic T lymphocyte (CTL) assay. For the antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent complement-mediated cytotoxicity (ACC) assays, TCs and SCs were prepared from normal male and female mice, respectively. Targets were labeled with Na₂⁵¹ CrO₄. The interactions of targets (TCs) and effectors (SCs) were conducted at 32.5°C (for CTL, ADCC, and ACC assays) or 37°C (for ACC assay). In the CTL assay, SCs from group 1 and group 2 caused significantly more killing than those from group 3. Specific cytotoxicity in the ADCC assay was only detected in the serum (maximum specific lysis 47.6%) of one mouse. No other cytotoxicity was detectable in 61 serum samples from group 1 (n = 25), group 2 (n = 17), and group 3 (n = 19). In the ACC assay, no significant specific cytolysis was found at different incubation temperatures (32.5 and 37.0°C) in 44 serum samples from the three groups. These results suggest that CTLs are important in the pathogenesis of experimental allergic orchitis (EAO). Adjuvant alone, probably because of breakdown of the blood-testis barrier, causes significant T lymphocyte cytotoxicity to TCs. ADCC and ACC are not important mechanisms in the immunopathogenesis of murine EAO.     

巨细胞病毒感染时免疫功能的变化及其意义

目的　探讨巨细胞病毒感染时免疫变化及其意义。方法　以 2 0名CMV IgM(Cytomegalovirus immunoglobulinM)阳性的病儿为观察对象 ,另设对照组 30例。ELISA法检测柯萨奇B组病毒抗原 (CVB Ag)、IgM抗体 (CVB IgM)、巨细胞病毒IgM抗体 (CMV IgM)、EB病毒IgM抗体 (EBV IgM) ,单克隆抗体标记间接ABC免疫法检测外周血T细胞亚群。结果　CMV感染组的LAK细胞、NK细胞活性均明显降低 (P <0 .0 1)。合并其它感染原的CMV混合感染组CD3含量减少 ,CD8含量增加 (P <0 .0 5 ) ,CD4 CD8数值明显降低 (P <0 .0 1)。病毒混合感染并合并支原体感染组CD3含量减少 (P <0 .0 5 )、CD4 CD8数值、IgA含量明显降低 (P <0 .0 1)。结论　巨细胞病毒感染影响了T细胞亚群的平衡 ,在合并其他感染时天然免疫细胞功能下降和T细胞亚群紊乱更明显     

细胞介导免疫在EAE发病中的作用

实验性变态反应性脑脊髓炎(简称EAE)是一种人工诱导的中枢神经系统自身免疫性疾病,也是自身免疫病的代表模式。关于EAE的免疫损伤机理,大多数学者认为致敏T细胞是引起EAE免疫损伤的主要原因;但也有报告指出:抗体也参与其损伤过程。有关这个问题的意见尚不统一。我们曾经在建立模型、提取髓磷脂硷蛋白(简称Bp)以及特异性免疫应答等方面做过一些工作。本文则以不同的实验手段和方法对EAE致病的主要原因作一系统观察,并对其可能的机理作出粗浅的分析。材料与方法一、动物及分组:豚鼠,由本校动物室供应。实验设有不同月龄组(4月龄,2 1/2月龄,1 1/2月龄)和新生期胸腺切除组,共4个组别,后者为2 1/2月龄,体重450g左右。各相应组别中,雌雄成比例分配。     

Chlamydia pneumoniae-Specific Cell-Mediated and Humoral Immunity in Healthy People

In this work, cell-mediated immunity to Chlamydia pneumoniae was studied in 157 healthy individuals using lymphoproliferative assay and serum antibodies were analysed by microimmunofluorescence techniques. The C. pneumoniae- specific IgG antibodies were elevated more frequently and the geometric mean titres for IgG (67.5 versus 44.1; P  = 0.05) and IgA (14.9 versus 11.3; P  = 0.025) antibodies were significantly higher in males than in females. However, no gender-dependent differences were observed in cellular reactivity to C. pneumoniae, since the median cellular responses were similar (stimulation indices 7.5) in men and women. Although the cell-mediated and humoral responses to C. pneumoniae did not correlate clearly, elevated IgG antibodies were associated with slightly higher lymphocyte proliferation in comparison to all subjects (15.5 versus 7.5) and significantly stronger in comparison to those with persistently elevated IgA (> 80) antibodies (15.5 versus 3.5; P  = 0.023). Further studies are needed to evaluate a possible role of reduced cellular reactivity in the cause of chronic C. pneumoniae infection.     

Manipulation of the superantigen-induced lymphokine response. Selective induction of interleukin-10 or interferon-γ synthesis in small resting CD4+ T cells

The production of several lymphokines by freshly isolated CD4⁺ T cells has been analyzed at the single-cell level, after stimulation with staphylococcal enterotoxin B (SEB). High frequencies of cells producing interleukin-2 (IL-2) and interferon-γ (IFN-γ) were induced, but very low frequencies of CD4⁺ T cells produced IL-4, IL-5 or IL-10 in response to SEB. Exogenously added IL-4 markedly altered the lymphokine profile induced during primary SEB stimulation. IFN-γ production was reduced, while a high fraction of cells contained IL-10 and IL-4 after activation in the presence of IL-4. We further demonstrate that IL-4 and IL-10 or IFN-y production was selectively induced in resting, high-density CD4⁺ T cells during primary stimulation, by SEB + IL-4 or SEB. Under conditions where both IL-10 and IFN-γ were produced, most cells contained only one of the two lymphokines.     

Depressed Cell-Mediated Immunity in Newborn Rabbits Bearing Fibroma Virus-Induced Tumors

Tumors were induced in adult and newborn rabbits by inoculation of fibroma virus. Whereas tumors completely regressed in adult rabbits by 3 weeks after virus inoculation, newborn rabbits supported tumor growth for 3 to 4 weeks. In the latter case, some animals died at this time, others survived with a gradual regression of the tumors over an additional period of 5 to 6 weeks. Virus neutralization studies demonstrated antibodies to fibroma virus in the serum from both adult and newborn tumor-bearing rabbits. Newborn rabbits with progressively growing tumors failed to elicit a delayed cutaneous hypersensitivity reaction to fibroma antigens, whereas adult rabbits showed strong reactions as early as 7 days after tumor induction. Similarly, macrophage migration inhibition tests revealed that the lymphocytes from newborn rabbits with progressively growing tumors were only weakly reactive to fibroma antigens, as compared to lymphocytes from adult tumorbearing rabbits. In contrast, newborn rabbits that survived and regressed the tumors demonstrated strong cell-mediated immunity both by skin testing and migration inhibition. Virus growth studies in cell culture demonstrated that fibroma was unable to replicate in peritoneal macrophages from either newborn or adult rabbits. No differences were observed in growth of the virus in macrophages from tumor-bearing rabbits. The significance of these observations is discussed in respect of the possible role of cell-mediated immunity in fibroma tumor regression.     

Multiple Sclerosis: Cell-Mediated Immunity to Human Brain Gangliosides

Cell-mediated immunity (CMI) to myelin components has been implicated in Multiple Sclerosis (MS) pathogenesis: two targets were suggested, Myelin Basic Protein with controversial results and, more recently, gangliosides. In order to investigate their possible involvement, we have performed Leukocyte Migration inhibition (LMI) tests in the presence of human brain gangliosides. Thirty nine MS patients (twenty four bcing “definite”, according to McDonald and Halliday's classification), twenty nine patients with Other Neurological Diseases (OND), thirty six patients with Inflammatory diseases (ID) and forty healthy controls were tested. MS patients wcrc divided into two groups, depending on the clinical stage of the disease.

The mean migration inhibiton percentage of the MS-attack group was found to be significantly different from the four others (p < 0.01) (24.4 ± 16.2 versus 10.9 ± 8.5 in MS without attack, 4.4 ± 12.9 in OND. 3.9 ± 13.9 in ID and 11.1 ± 12.1 in healthy subjects). LMI to gangliosides is therefore significantly increased during the attack stage in MS. These results support the notion of a Delayed Type Hypersensitiv-ity to these glycolipids during the active stage of the disease.