Generation of human cytomegalovirus-specific cytotoxic T-lymphocytes in a short-term culture

A method to generate human cytomegalovirus (HCMV)-specific CTL (cytotoxic T lymphocytes) from human peripheral blood mononuclear cells is described. This assay is unique in comparison with other methods reported to date, because it only requires a short-term (6 days) coculture of PBM and autologous infected fibroblasts without the addition of exogenous IL-2 (interleukin-2) and nevertheless is sensitive enough to determine HCMV-specific killing in a short (6 h) 51Cr-release assay using autologous HCMV-infected fibroblasts as targets. The virus-specific killing is mediated by CTL of the CD8 phenotype and it can be inhibited by a HLA class I monoclonal antibody. The sensitivity of the assay can be significantly enhanced by pretreating the targets with interferon-gamma (IFN-gamma) prior to infection with HCMV. HCMV-specific 51Cr-release is more than doubled when the IFN-gamma pretreated targets are used. This increase is mostly due to enhanced sensitivity of the fibroblasts to killing mediated by CD8-positive CTL, but some killing can be attributed to CTL of the CD4 phenotype.

Possible regulation of autologous mixed lymphocyte reaction by OKM1+ NK cells

T cells are stimulated by autologous non-T cells and interleukin 2 (IL-2) is produced in the conventional autologous mixed lymphocyte reaction (AMLR) in young healthy controls. The role of cells with natural killer (NK) cell markers (OKM1+ cells or Leu 7+ cells) in the AMLR was studied. There were significant inverse correlations between the percentage of input OKM1+ cells minus monocyte (OKM1+ NK cells) and either AMLR proliferation (gamma = -0.9, P less than 0.001) or IL-2 production (gamma = -0.75, P less than 0.01) in the AMLR cultures after 7 days measured at 7 days. A statistically significant correlation was observed between the percentage of input Leu 7+ cells and AMLR proliferation (gamma = -0.64, P less than 0.05), but not IL-2 production. These results suggest that the AMLR is controlled by OKM1+ NK, perhaps acting through IL-2 regulation.

Cytokines in chronic inflammatory synovitis

Cytokines likely play a role in the pathogenesis of rheumatoid arthritis and other chronic inflammatory arthritidies. Recent studies on the cytokine profile of inflammatory synovitis have provided insight into the mechanisms of cellular activation in the inflamed joint. Although gamma interferon has been proposed as a major macrophage activating factor and inducer of class II major histocompatibility antigens in the joint, studies using sensitive and specific immunoassays have shown that the concentration of this lymphokine in synovial fluid is probably not sufficient to account for the high level of HLA-DR expression on Type A synoviocytes and macrophages in the joint. In contrast, GM-CSF has recently been identified in synovial effusions of patients with rheumatoid arthritis and is produced by synovial tissue cells in vitro. Like gamma interferon, GM-CSF is a known macrophage activating factor and induces HLA-DR on cells of macrophage lineage. Furthermore, supernatants of cultured synovial tissue cells contain an HLA-DR inducing factor that is neutralized by specific antibodies to GM-CSF but not by antibodies to gamma interferon. These data suggest that GM-CSF plays a significant role in macrophage activation in the synovium.

The pathogenesis of rheumatoid arthritis. A critical assessment of the role of autologous stimulation in the perpetuation of rheumatoid synovitis

Current models for rheumatoid arthritis emphasize the role of activated T cells and their products in the pathogenesis of synovitis. The data supporting this view are critically reviewed in this article and inconsistencies are discussed. To resolve these contradictions, the authors propose that rheumatoid synovitis represents a localized autologous mixed lymphocyte reaction.

Cellular immunity in the joints of patients with rheumatoid arthritis and other forms of chronic synovitis

Rheumatoid arthritis (RA), although a systemic illness, is primarily a synovial disease. Morphologic and functional studies of immune cells within the synovium strongly suggest that disordered cellular immunity is key to the pathogenesis of RA. This article describes in detail the various cells found within the rheumatoid joint and compares them with those found in nonrheumatoid synovitis and in normal peripheral blood.

Alterations in immune responsiveness in women exposed to diethylstilbestrol in utero

In order to study the effect of in utero diethylstilbestrol (DES) exposure on the immune system of adult women, the blastogenic response of peripheral blood lymphocytes to two mitogens was compared in eight DES-exposed patients and in eight age-matched controls with normal menstrual cycles and proven fertility. As measured by the uptake of 3H-thymidine (mean [+/- standard error]), response to the T-cell mitogen phytohemagglutin (PHA) was significantly higher (P less than 0.002) in cells of DES-exposed women (88.6 +/- 5.7 X 10(3) cpm) than in controls (44.0 +/- 8.9 X 10(3) cpm) at the lowest dose of mitogen tested (0.125 microgram/ml). Moreover, lymphocytes of DES-exposed subjects showed maximal blastogenic response to PHA at a concentration (0.125 microgram/ml) two to four times lower (P less than 0.002) than controls (0.25 microgram/ml to 0.5 microgram/ml). Cells of both DES-exposed subjects and controls were maximally responsive to pokeweed mitogen (PWM) at the lowest dose tested (0.625 microgram/ml). These findings suggest that in utero DES exposure is associated with a hyper-reactive immune response during the reproductive years.

Peripheral blood and synovial fluid monocyte activation in inflammatory arthritis. II. Low levels of synovial fluid and synovial tissue interferon suggest that gamma-interferon is not the primary macrophage activating factor

Because synovial fluid monocytes (SFM) in patients with inflammatory arthritis bear an activated phenotype (i.e., high expression of HLA-DR and low expression of the monocyte differentiation antigen Mo2), we assessed the role of gamma-interferon (gamma-IFN) in the activation of these cells. Sensitive and specific radioimmunoassays detected only 0.40 +/- 0.20 units/ml of gamma-IFN in the SF of patients with rheumatoid arthritis (RA) and 0.61 +/- 0.67 units/ml of gamma-IFN in the SF of patients with other forms of chronic inflammatory arthritis. There was no detectable alpha-IFN in any SF studied by radioimmunoassay. Bioassays failed to detect nonimmunoreactive IFN. Synovial tissue (ST) explants produced very little gamma-IFN (0.14 +/- 0.091 units/ml), and production was not increased by the presence of indomethacin in the cultures or by removal of adherent cells. However, gamma-IFN was produced if ST was cultivated in the presence of phytohemagglutinin. In SF and ST supernatants, gamma-IFN-mediated induction of HLA-DR on monocytes was inhibited, even though the amount of immunoreactive IFN was not affected. Prostaglandin E2 was shown to be one possible inhibitor. We demonstrated that a factor that induces HLA-DR on some individuals' peripheral blood monocytes, and cannot be neutralized by monoclonal anti-gamma-IFN antibody, is present in SF and ST supernatants. These data suggest that activation of SFM may occur by mechanisms other than gamma-IFN.

Peripheral blood and synovial fluid monocyte activation in inflammatory arthritis. I. A cytofluorographic study of monocyte differentiation antigens and class II antigens and their regulation by gamma-interferon

Recent study of the expression of monocyte differentiation antigens (MAg) and HLA-DR on peripheral blood monocytes (PBM) has led to the recognition of resting and activated monocyte phenotypes. The former is identified by the expression of large amounts of MAg (i.e., Mo2 and 63D3) and small amounts of HLA-DR, while the latter is identified by the reverse. We studied the phenotypes of PBM and synovial fluid monocytes (SFM) of patients with chronic inflammatory arthritis and found that PBM were primarily resting and SFM were usually activated. In addition, we measured the degree of modulation of MAg and HLA-DR by gamma-interferon (gamma-IFN). Patient PBM reacted the same as PBM from normal individuals (i.e., MAg decreased and HLA-DR increased after exposure to gamma-IFN). However, in patient SFM, HLA-DR did not increase with exposure to gamma-IFN because expression was already maximal. Interestingly, MAg could still be down-regulated on gamma-IFN-treated SFM, even when expression began at a very low level (i.e., activated phenotype). This independent regulation of MAg and HLA-DR suggests that macrophage activating factors other than gamma-IFN may be responsible, in part, for the activated phenotypes observed.

Down regulation of human monocyte differentiation antigens by interferon gamma

The role of IFN-gamma in the activation and differentiation of human peripheral blood monocytes was investigated. Recombinant IFN-gamma induced a decrease in the expression of monocyte differentiation antigens (Mo2 and 63D3) and, to a lesser extent, the C3bi receptor. Conversely, class II histocompatibility antigen expression increased on monocytes exposed to IFN-gamma. The antigen modulating effect of IFN-gamma was maximal on freshly isolated monocytes, with diminished potency if added to monocytes that had been cultivated in vitro for 1 to 3 days. Experiments to determine the fate of the down-regulated antigens on interferon-treated cells failed to demonstrate intracellular antigen due to internalization. We suggest that Mo2 and 63D3 may be considered "inverse" activation antigens; i.e., their expression is decreased in monocytes activated by interferon.

Reactive arthritis

Inflammatory arthritis occurring days to weeks after a localized infection is known as reactive arthritis. Epidemiologic, genetic, and immunologic features have established this disease as a distinct clinicopathologic entity. Although reactive arthritis is often a transient disease, many individuals suffer a chronic relapsing course. Treatment is usually conservative except in a minority of cases in which patients require remittive therapy.

Regulation of the growth of Epstein-Barr virus-infected B cells: temporal profile of the in vitro development of three distinct cytotoxic cells

The time course of the appearance of cytotoxic cells was examined in cocultures of E-rosetting (E+) cells and EBV-infected non-T cells (4:1 ratio) from the blood of VCA-positive healthy adults. Classical HNK-1+ NK cells were present at the initiation of the cultures and they produced 76 +/- 2% specific 51Cr-release from K-562 cells, but they did not effectively lyse the NK-resistant Daudi cells, nor did they kill autologous EBV-induced lymphoblasts (LCLEBV). The NK activity decreased during the first week in culture to 40 +/- 7% cytotoxicity. At the same time, nonspecific cytotoxic cells capable of killing Daudi as well as K562 developed and persisted into the third week in culture when it declined. This later nonspecific cytotoxicity was mediated by 4F2+, T8-, HNK-1- activated E+ cells. After 10 days in culture, killing of autologous LCLEBV increased continuously, from 4 +/- 3% at Day 10 to 38 +/- 4% by Day 22. The cytotoxicity to LCLEBV was mediated by classical T8+ CTL, and it was antigen specific and at least partially HLA Class I restricted. The regression of BEBV growth that occurs in E+/BEBV cocultures coincides with the development of this CTL-mediated cytotoxicity.

Characterization of the precursors of the NK-like cytotoxic cells generated in the autologous mixed leukocyte reaction and by interleukin 2 activation

In vitro stimulation of E+ cells with autologous E- cells (AMLR) for 7 days results in the generation of NK-like killer cells with the same phenotype (E+, 4F+2, OKT-8, OKM-1) as the killer cells produced by activation of E+ cells with IL-2 for 3 days in our system. IL-2 activity was also detected in the course of AMLR culture in concordance with the generation of the killer cells. These data prompted us to characterize the progenitor cells in the 2 systems by using positive (panning) or negative (complement mediated cytolysis) selection techniques. The NK-like killer cells generated from both the AMLR responder population and by activation with IL-2 are derived from the same population of cells with an E+, OKM+1 but not Leu 7+ phenotype.

Identification of immunostimulatory dendritic cells in the synovial effusions of patients with rheumatoid arthritis

Dendritic cells in the circulation are leukocytes that are rich in Ia antigens and that actively stimulate T cell replication. We have identified dendritic cells in the joint effusions of patients with rheumatoid arthritis. By phase-contrast and immunofluorescence microscopy, synovial mononuclear cells contained 1-5% dendritic profiles that were rich in HLA-DR and DQ, had small amounts of C3bi receptor, and lacked a battery of monocyte and lymphocyte markers. These dendritic cells could be enriched to 60-80% purity by cytolytic depletion of monocytes and lymphocytes with a group of monoclonal antibodies (MAb) and complement. By transmission electron microscopy, the dendritic cell processes were bulbous in shape and lacked organelles. The cytoplasm had few lysosomes or endocytic vacuoles but contained a well-developed smooth reticulum that was comparable to that previously described in the Ia-rich interdigitating cells of lymphoid tissues. The growth of sodium periodate-modified T lymphocytes was used as a rapid quantitative assay of accessory cell function. Synovial mononuclear cells were some ten times more active than normal blood cells. Treatment with alpha-Ia MAb and complement ablated stimulatory function. In contrast, removal of monocytes (MAb, 3C10) or monocytes and B (MAb, BA-1) plus T (MAb, OKT3, or T101) lymphocytes did not significantly alter total activity, and the function per viable cell increased four- to eightfold. We conclude that rheumatoid arthritis synovial fluids contain cells that are comparable in function, phenotype, and structure to blood dendritic cells, although the frequency (1-5%) is 10 times greater in joints. The reason for their accumulation in the articular cavity is not known, but dendritic cells may be important in perpetuating the joint inflammation characteristic of this disease.

Idiopathic regional osteoporosis: a clinical spectrum

Regional migratory osteoporosis (RMO) and transient osteoporosis of the hip are entities characterized by osteopenia of periarticular bone. They are considered separate disorders because the clinical setting and pattern of joint involvement in each is reportedly different. We have observed 3 patients whose overlapping features lead us to believe that rather than being distinct entities, RMO and transient osteoporosis may be examples of the same spectrum of disease.

Mouth and genital ulcers with inflamed cartilage: MAGIC syndrome. Five patients with features of relapsing polychondritis and Behçet's disease

Five patients with features of coexistent relapsing polychondritis and Behçet's disease are described. Review of the literature supports the overlap of the clinical manifestations of these two conditions. A common immunologic abnormality is likely, and elastin is cited as a possible target antigen. The "mouth and genital ulcers with inflamed cartilage (MAGIC) syndrome" is the proposed name for this entity.

Impaired killer cell generation in the autologous mixed leukocyte reaction by rheumatoid arthritis lymphocytes

Natural killer-like cells are generated along with interleukin-2 (IL-2) in the autologous mixed leukocyte reaction (AMLR). Patients with active rheumatoid arthritis (RA), but not those whose disease is in remission, are poor producers of AMLR killer cells. This defect cannot be explained by age, medications, or serum factors. The impaired generation of natural killer-like cells was not influenced by gamma-interferon but could be partially restored by addition of indomethacin to the AMLR culture, or by culturing RA T cells with exogenous IL-2. However, the response of RA T cells to IL-2 was significantly less than that of controls. These results suggest that the defect in the generation of AMLR killer cells in patients with active RA may be due in part to defective production of IL-2 and a lesser sensitivity of RA T cells to IL-2.

Regulation of the growth of Epstein-Barr virus-infected B cells. I. Growth regression by E rosetting cells from VCA-positive donors is a combined effect of autologous mixed leukocyte reaction and activation of T8+ memory cells

Regression of B cell proliferation in co-cultures of EBV-infected B cells (BEBV) and autologous T cells at 1:4 ratio was studied. 3H-TdR incorporation was used to measure proliferation by the participating lymphocyte populations and a 51Cr release assay was used to document the generation of cells capable of killing autologous EBV-transformed B lymphoblastoid cell lines (LCLEBV). EBV-infected B cells cultured alone transformed to blasts by culture day 10, and continued to proliferate throughout the 22 day observation period. When EBV-infected B cells were co-cultured with E rosetted cells from VCA-positive donors, there was a characteristic proliferative response on day 10 (an augmented autologous mixed lymphocyte reaction; AMLR), followed by the development of T8+ cells capable of killing autologous LCLEBV, as well as over 90% suppression of EBV growth by day 22 as assessed by 3H-TdR incorporation, and confirmed in a visual outgrowth assay. Negative and positive selection techniques were used to define the regulatory components in the T cell population. Depletion of T8+ cells from the blood lymphocytes of VCA-positive donors did not significantly reduce the 10 day proliferative response, but the subsequent development of cytotoxic cells and the regression of BEBV outgrowth was not observed. Thus, the circulating T8+ cells are required for the subsequent appearance of autologous LCLEBV cytotoxicity and BEBV growth regulation. However, when the responder population consisted only of T8+ cells, the augmented AMLR response was absent, cytotoxic cell development was weak or absent, and there was no regression of EBV outgrowth. Therefore, the cells participating in the AMLR, as well as T8+ memory cells from VCA-positive donors, are necessary for the control of the in vitro EBV infection. Growth regression is dependent on the proliferation of the regulatory T cells. Mitomycin C treatment of fresh E rosetting cells or those exposed to BEBV for up to 10 days in culture abrogates growth regression and the subsequent appearance of LCLEBV killer cells. However, E rosetting cells exposed to BEBV for 14 days or more already have developed the ability to kill LCLEBV and no longer need to proliferate to induce growth regression when cultured with newly infected BEBV. These results lend additional support to the view that the control of EBV-induced B cell expansion requires a AMLR-dependent clonal amplification of EBV-specific, T8+ cytotoxic cells.

Regulation of the growth of Epstein-Barr virus-infected B cells. I. Growth regression by E rosetting cells from VCA-positive donors is a combined effect of autologous mixed leukocyte reaction and activation of T8+ memory cells

Regression of B cell proliferation in co-cultures of EBV-infected B cells (BEBV) and autologous T cells at 1:4 ratio was studied. 3H-TdR incorporation was used to measure proliferation by the participating lymphocyte populations and a 51Cr release assay was used to document the generation of cells capable of killing autologous EBV-transformed B lymphoblastoid cell lines (LCLEBV). EBV-infected B cells cultured alone transformed to blasts by culture day 10, and continued to proliferate throughout the 22 day observation period. When EBV-infected B cells were co-cultured with E rosetted cells from VCA-positive donors, there was a characteristic proliferative response on day 10 (an augmented autologous mixed lymphocyte reaction; AMLR), followed by the development of T8+ cells capable of killing autologous LCLEBV, as well as over 90% suppression of EBV growth by day 22 as assessed by 3H-TdR incorporation, and confirmed in a visual outgrowth assay. Negative and positive selection techniques were used to define the regulatory components in the T cell population. Depletion of T8+ cells from the blood lymphocytes of VCA-positive donors did not significantly reduce the 10 day proliferative response, but the subsequent development of cytotoxic cells and the regression of BEBV outgrowth was not observed. Thus, the circulating T8+ cells are required for the subsequent appearance of autologous LCLEBV cytotoxicity and BEBV growth regulation. However, when the responder population consisted only of T8+ cells, the augmented AMLR response was absent, cytotoxic cell development was weak or absent, and there was no regression of EBV outgrowth. Therefore, the cells participating in the AMLR, as well as T8+ memory cells from VCA-positive donors, are necessary for the control of the in vitro EBV infection. Growth regression is dependent on the proliferation of the regulatory T cells. Mitomycin C treatment of fresh E rosetting cells or those exposed to BEBV for up to 10 days in culture abrogates growth regression and the subsequent appearance of LCLEBV killer cells. However, E rosetting cells exposed to BEBV for 14 days or more already have developed the ability to kill LCLEBV and no longer need to proliferate to induce growth regression when cultured with newly infected BEBV. These results lend additional support to the view that the control of EBV-induced B cell expansion requires a AMLR-dependent clonal amplification of EBV-specific, T8+ cytotoxic cells.

Characterization of the natural killer-like lymphocytes in rheumatoid synovial fluid

IgG Fc- cytotoxic cells found in the synovial fluid of patients with rheumatoid arthritis have natural killer (NK)-like characteristics but can kill NK-resistant cell lines as well. The phenotype of these cells was defined by complement-mediated lysis with monoclonal antibodies. The synovial fluid killer cell activity was significantly reduced by treatment with complement and OKT11 and 4F2, but the cytotoxic T cells did not express the NK-related antigens OKM1 and Leu-7, nor the cytotoxic T lymphocyte-specific antigen, OKT8. These results demonstrate that the synovial fluid killer cells resemble the activated T cells generated in an autologous mixed leukocyte reaction or in the treatment of peripheral blood mononuclear cells with interleukin 2, and they are distinct from the conventional NK cells found in blood.

Characterization of the natural killer-like lymphocytes in rheumatoid synovial fluid

IgG Fc- cytotoxic cells found in the synovial fluid of patients with rheumatoid arthritis have natural killer (NK)-like characteristics but can kill NK-resistant cell lines as well. The phenotype of these cells was defined by complement-mediated lysis with monoclonal antibodies. The synovial fluid killer cell activity was significantly reduced by treatment with complement and OKT11 and 4F2, but the cytotoxic T cells did not express the NK-related antigens OKM1 and Leu-7, nor the cytotoxic T lymphocyte-specific antigen, OKT8. These results demonstrate that the synovial fluid killer cells resemble the activated T cells generated in an autologous mixed leukocyte reaction or in the treatment of peripheral blood mononuclear cells with interleukin 2, and they are distinct from the conventional NK cells found in blood.

The role of xenoantigen in the human autologous mixed lymphocyte reaction: ability to respond in the absence of exposure to xenoantigen depends on the method of T-cell preparation

Recent reports have suggested that the autologous mixed lymphocyte reaction (AMLR) is attributable to contaminating xenoantigen. T-cell populations separated from peripheral blood mononuclear cells (PBM) over Percoll fail to produce an AMLR in the absence of xenoantigen. However, T-cell populations that do not adhere to plastic and to nylon wool will in the absence of added xenoantigen produce an AMLR comparable to that obtained with E-rosetted populations. In the nonadherent cells separated sequentially by passage through nylon wool and Percoll, the presence of two lymphocyte subpopulations was demonstrated. One is xenoantigen dependent, the other xenoantigen independent in the AMLR. Further, the xenoantigen-independent population may provide help to the dependent population. In the previous reports with Percoll-separated cells that attributed the AMLR to contaminating xenoantigen, the xenoantigen-independent T-cell population was excluded from the responding fraction.

Panning separation for monoclonal antibody-specific T-cell subsets: effects of enzymes and metabolic inhibitors

The mechanisms of "panning," a simple positive cell separation technique, were examined. Using monoclonal antibodies to "pan" for T cells (T101+, T4+, and T8+), we obtained enriched populations with 90% purity and viability from unfractionated human peripheral blood lymphocytes (PBL). We found that the "panning" method reflects an active process. It is sodium azide inhibitable and independent of the divalent cation concentration. Effective panning does not require capping, patch formation, or DNA synthesis. The cell yields are unaffected by mitomycin-C or microtubule and microfilament blocking reagents such as concanavalin A, colchicine, and cytochalasin B. This economical technique provides large numbers of functionally intact monoclonal antibody-specific cells within a relatively short time for further functional and biochemical characterization.