Demonstration of the Th1 to Th2 cytokine shift during the course of HIV-1 infection using cytoplasmic cytokine detection on single cell level by flow cytometry

OBJECTIVE: To characterize changes of Th1/Th2 cytokine production by peripheral blood mononuclear cells (PBMC) that occur during the course of HIV infection by cytoplasmic cytokine staining on single cell level. DESIGN AND METHODS: Mitogen-stimulated PBMC from 16 healthy donors, 18 HIV-1-infected individuals without AIDS and 14 patients with AIDS were stained intracellularly with fluorescein-labelled MAb against interleukin (IL)-2, IL-4, IL-10 and interferon (IFN)-gamma. Additionally, co-staining of CD4+ T-cell, CD8+ T-cell, natural killer (NK) cell, B-cell and monocytic markers was performed. Fluorescence staining was analysed by three-colour flow-cytometry. RESULTS: A reduced percentage of IL-2 and IFN-gamma (Th1 type)-producing cells among CD4+ T cells from HIV-1-infected individuals could be demonstrated. There was a continuous decrease of IFN-gamma-producing CD4+ T cells in the course of HIV infection and a dramatic reduction of IL-2-expressing cells among CD4+ T cells in patients with AIDS. In contrast to Th1 cytokines, the frequency of Th2 cytokine expressing cells among CD4+ T cells increased in HIV-infected individuals. The maximum frequency of IL-4-expressing cells among CD4+ T cells was seen in HIV-infected individuals without AIDS, whereas the rate of IL-10-producing cells was highest in patients with AIDS. In HIV-infected individuals no significant proportion of Th0 cells expressing both Th1 and Th2 cytokines was detectable. In CD8+ T cells the percentage of IL-2 was expressing cells decreased continuously accompanied by a strong increase of the frequency of IFN-gamma-producing cells. CONCLUSION: The decreased percentage of cells expressing IL-2 and IFN-gamma in conjunction with an increased proportion of IL-4- and IL-10-producing cells among the CD4+ T cells in HIV-1-infected individuals demonstrate a Th1 to Th2 cytokine shift in the course of HIV infection on a single cell level. There was no evidence of a Th1 to Th0 cytokine shift. In addition to the loss of CD4+ T cells in HIV infection, the qualitative changes of Th1/Th2 cytokine expression may serve as a marker for progressive failure of cell-mediated immunity.     

Anti-fungal and cytokine producing activities of CD8 + T lymphocytes from HIV-1 infected individuals

Lymphokine activated killer (LAK) cells are capable of killing not only malignant cells but also hyphal form of Candida albicans in vitro. When peripheral blood mononuclear cells (PBMC) from normal healthy donors were cultured for 72-96 hrs with 1,500 international unit (IU)/ml interleukin-2 (IL-2), marked LAK activity was induced. However, even prior to IL-2 activation, PBMC isolated from some normal subjects and those from almost all individuals who are infected by human immunodeficiency virus type 1 (HIV-1) exhibited significant levels of anti-fungal activity. Such pre-activation ("in situ") antifungal activity of PBMC decreased during the initial 48 hrs of IL-2 activation. PBMC from HIV-1 seropositive subjects showed higher levels of "in situ" anti-fungal activity than normal PBMC did. After a decline of "in situ" activity during the initial 48 hours, LAK activity gradually increased and reached near maximal levels by day 4 and remained more or less constant until day 6. No significant difference was observed between the LAK activity of normal and HIV-1(+) PBMCs on days 4-6. In IL-2 activated normal and HIV-1(+) PBMC cultures, both CD4 and CD8 T cells produced IL-2, INF-gamma as well as TNF-alpha. Production of IL-2 by both CD4 and CD8 T cells was suppressed in HIV-1(+) PBMC cultures, but no significant suppression of INF-gamma production was noted. Meanwhile, TNF-alpha production by CD4 was very much suppressed but no significant changes in TNF-alpha production by CD8 T cells was noted in HIV-1(+) PBMC cultures.     

Analysis of type 1 and type 2 T cells in synovial fluid and peripheral blood of patients with rheumatoid arthritis

OBJECTIVE: It has been reported that CD4+ helper T cells play an important role in the pathogenesis of rheumatoid arthritis (RA). We evaluated the presence of intracellular cytokines interleukin 4 (IL-4) and interferon-gamma (IFN-gamma) produced by CD4+ and CD8+ T cells in the synovial fluid and peripheral blood of patients with RA at the single cell level. METHODS: We used 3 color flow cytometric analysis. Synovial fluid mononuclear cells (SFMC) and peripheral blood mononuclear cells (PBMC) were stimulated with phorbol myristate acetate (PMA) and calcium ionophore. The stimulated SFMC and PBMC were triple stained with conjugated mononuclear antibodies (Mab) against cytokines and surface antigens after fixation and permeabilization with a saponine buffer solution. The cells were analyzed for intracellular cytokines (IFN-gamma, IL-4) and surface antigens (CD3, CD4, CD8) using a flow cytometer. RESULTS: The CD4/CD8 ratio was significantly lower in SFMC than in PBMC. The positive rates of IFN-gamma producing cells among CD4+ T cells were significantly higher than those of IL-4 producing cells in both the SFMC and the PBMC of patients with active RA. In the SF of these patients, we also found CD8+ T cells that produce IL-4 alone, or both IL-4 and IFN-gamma. CONCLUSION: In the SF of patients with RA, CD4+ type 1 T cells, which may infiltrate into the synovium and cause pathogenic immune responses in the tissue, are predominant. We believe this cell type also induces migration and activation of CD8+ type 2 T cells into the active site of inflammation, which appears to downregulate the activity of CD4+ type 1 T cells, modulating the excess immune response.     

Increased in vitro induced CD4+ and CD8+ T cell IFN-gamma and CD4+ T cell IL-10 production in stable relapsing multiple sclerosis

Multiple sclerosis (MS) is presumed to be a T-cell mediated chronic inflammatory disease of the central nervous system. Investigators previously demonstrated increased IFN-gamma (pro-inflammatory) and IL-10 (counterregulatory anti-inflammatory) in MS. The balance of pro-inflammatory and counterregulatory anti-inflammatory cytokines may be important in the stabilization of disease activity. Purified CD4+ and CD8+ T cells from patients with clinically definite, stable relapsing MS (RRMS) were stimulated by anti-CD3 mAb or Con A for 48 hours and cytokine supernatants analysed for production of IL-2, IL-6, IFN-gamma, TNF-alpha (potential pro-inflammatory) and IL-4, IL-10, and TGF-beta (potential counterregulatory anti-inflammatory). Con A activated CD4+ and CD8+ T cell proinflammatory cytokine IL-2 secretion, CD4+ T cell IL-6 secretion, CD4+ and CD8+ T cell TNF-alpha secretion and CD8+ T cell IFN-gamma secretion was decreased significantly in RRMS subjects compared to controls. CD3 activated CD4+ and CD8+ T cell IL-6 secretion and CD4+ T cell TNF-alpha secretion was significantly decreased in MS subjects compared to controls. In contrast, there was increased CD3-induced IFN-gamma in both CD4+ and CD8+ T cells and counterregulatory anti-inflammatory CD3-induced IL-10 secretion in CD4+ T cells in RRMS compared to controls. These data suggest that an equilibrium of a pro-inflammatory (IFN-gamma) and a counterregulatory anti-inflammatory (IL-10) cytokine may define stable clinically definite early RRMS.     

On-farm monitoring of mouse-invasive Salmonella enterica serovar enteritidis and a model for its association with the production of contaminated eggs

CD4 molecules are the primary receptors for human immunodeficiency virus (HIV) and bind the envelope glycoprotein gp120 of HIV with high-affinity. We have previously shown that cross-linking of CD4 molecules (CD4XL) in normal peripheral blood mononuclear cells (PBMC) results in secretion of cytokines tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), but not of interleukin-2 (IL-2) or IL-4. To investigate the intracellular signaling events associated with CD4-gp120 interaction, we incubated CD4+ T cells from peripheral blood of HIV-negative healthy donors with HIV envelope protein gp160 alone or performed CD4XL with gp160 and anti-gp160 antibody. This procedure resulted in tyrosine phosphorylation of intracellular substrates p59fyn, zap 70, and p95vav and also led to ras activation, as assessed by conversion of rasGDP to rasGTP. The role of ras in CD4 signaling was further investigated using CD4+ Jurkat cells transfected with a dominant negative ras mutant. CD4+ T cells expressing dn-ras secreted significantly reduced levels of TNF-alpha in response to CD4XL. These studies indicate that interaction of HIV gp160 with CD4 molecules activates the ras pathway in T cells, which may result in the cells becoming unresponsive to subsequent stimulation.     

Effect of d-fenfluramine on the lymphocyte response of HIV+ humans

The objective of this study was to analyse the effect of d-dexfenfluramine (d-FEN) on the human lymphocyte response, in vitro. Experiments were designed to determine whether d-FEN augments specific human immune parameters associated with protection from opportunistic microbial pathogens and particularly focuses on d-FEN as a means by which to augment the function of CD8+ and CD4+ lymphocytes. Lymphocytes were examined for three reasons: (1) for their ability to inhibit the growth of Candida albicans; (2) for their ability to proliferate in response to a mitogen; and, (3) their cytokine profile (vis., production of IL-2, IFN-gamma and TNF-alpha). Peripheral blood mononuclear cells (PBMC) were obtained from 20 HIV+ patients. The patients were diagnosed as HIV+ within the past 0.5-9 years. d-FEN was found to augment the capacity of CD8+ lymphocytes to inhibit the growth of the opportunistic microbial pathogen, C. albicans. d-FEN enhanced the capacity of CD4+ lymphocytes to proliferate in response to the mitogen, Concanavalin A, and to increase the amount of IL-2 produced by CD4+ and CD8+ lymphocytes from AIDS patients. d-FEN increased the number of CD4+ and CD8+ lymphocytes that produced IFN-gamma from either non-AIDS or AIDS patients and increased the number of AIDS patient's CD8+ lymphocytes that produce TNF-alpha. These in vitro data suggest that d-FEN may be effective in enhancing immune function in immunocompromised individuals.     

The advantages and disadvantages of the cytokinesis-block micronucleus method

Until recently, chimpanzees were considered susceptible to human immunodeficiency virus type 1 (HIV-1) infection, but refractory to disease induction based on the asymptomatic status of all experimentally infected chimpanzees after over 10 years postinfection (PI). However, a decline in peripheral CD4+ T cells was noted in one chimpanzee (C499) of the Yerkes cohort of HIV-1 infected apes, after 11 years PI concurrent with increasing plasma viral load. These clinical signs were followed by the occurrence of opportunistic infections, thrombocytopenia, and progressive anemia leading to euthanasia. A second chimpanzee (C455) was transfused with blood from C499 collected during the symptomatic stage. Shortly thereafter, this second animal showed a rapid decline in peripheral CD4+ T-cell levels and sustained high viral load. Hematological analyses showed a 50% decrease in CFU-GM for both apes during the symptomatic phase and a reduction of 40% and 73% of the total CFU despite normal levels of CD34+ cells in the bone marrow. Cryopreserved sequential PBMC samples from these two chimpanzees were analyzed for constitutive and PHA-P induced levels of cytokines and chemokines. Data show that whereas there were no detectable constitutive levels of mRNA coding for IL-2, 4, and 10, there appears to be a transient increase in IFN-gamma message level coincident with increased viremia and this IFN-gamma synthesis decreased with disease progression. PHA-induced cytokine mRNA analysis showed low or undetectable levels of IL-4 and IL-10 mRNA in all samples and a marked decrease in the levels of IL-2 shortly after HIV infection. In addition, there was also a gradual decrease in IFN-gamma mRNA with progression of disease. Of interest were the findings of high to normal levels of PHA-induced synthesis of the chemokines MIP-1alpha, MIP-1beta, and RANTES in samples during the asymptomatic and early symptomatic period, which also dramatically decreased at late stages of the disease. These data suggest important roles for IL-2, IFN-gamma, and the chemokines in the regulation of immune responses in HIV-1-infected chimpanzees.     

Effects of beta2 adrenoceptor agonists on T-cell subpopulations

The aim of the present communication is to determine the effects of beta2 adrenoceptor agonists on growth and cytokine secretion using allergen-specific T cells. Four beta2 adrenoceptor agonists were administered at therapeutically relevant doses (salbutamol 1-2 microM; salmeterol 0.03-0.06 microM; terbutaline 0.56-1.12 microM, and fenoterol 0.7-1.4 microM to: a) Cultures of human peripheral mononuclear cells (PBMC) b) Positively selected CD4+ and CD8+ subsets, c) Allergen-specific T-cell lines (TCL). Drug effects on growth kinetics and the secretion of IL-4, IL-5, INF-gamma and IgE following T-cell stimulation were investigated. Comparing the growth inhibitory effect of the 4 beta2 agonists at 2 different concentrations, using 12 PBMC, 10 CD4+ and CD8+ and 10 TCL cultures, the following patterns were observed: PBMC-, CD4+- and CD8+-cultures: salmeterol, followed by salbutamol and fenoterol, was a more potent inhibitor than terbutaline. In long-term TCL-cultures, salmeterol was the most potent drug, followed by fenoterol. No significant differences were observed between salbutamol and terbutaline. TCL secretion of IL-4 and IL-5 (TH2 cytokines) was also significantly inhibited. In one patient, INF-gamma secretion (TH1/THO cytokine) could be enhanced by drug administration. High IgE secretion, from 1% remaining B cells in one of the patients, following PHA+IL-2 stimulation, could be reduced by the drugs. The results showed that the beta2 agonists could influence T-cell growth and function. The changes regarding cell function were individual and related to T-cell phenotypes secreting TH1/THO or TH2 cytokines. These results suggest that administration of beta2 adrenoceptor agonists could be beneficial, not only for bronchodilation, but also for suppressing the underlying inflammatory process dominated by TH2-like cytokine secretion.     

Interleukin-12 primes human CD4 and CD8 T cell clones for high production of both interferon-gamma and interleukin-10

Interleukin-12 (IL-12) induces differentiation of T helper 1 (Th1) cells, primarily through its ability to prime T cells for high interferon-gamma (IFN-gamma) production. We now report that the presence of IL-12 during the first several days of in vitro clonal expansion in limiting dilution cultures of polyclonally stimulated human peripheral blood CD4+ and CD8+ T cells also induces stable priming for high IL-10 production. This effect was demonstrated with T cells from both healthy donors and HIV+ patients. Priming for IL-4 production, which requires IL-4, was maximum in cultures containing both IL-12 and IL-4. IL-4 modestly inhibited the IL-12-induced priming for IFN-gamma, but almost completely suppressed the priming for IL-10 production. A proportion of the clones generated from memory CD45RO+ cells, but not those generated from naive CD45RO- CD4+ T cells, produced some combinations of IFN-gamma, IL-10, and IL-4 even in the absence of IL-12 and IL-4, suggesting in vivo cytokine priming; virtually all CD4+ clones generated from either CD45RO(-) or (+) cells, however, produced high levels of both IFN-gamma and IL-10 when IL-12 was present during expansion. These results indicate that each Th1-type (IFN-gamma) and Th2-type (IL-4 and IL-10) cytokine gene is independently regulated in human T cells and that the dichotomy between T cells with the cytokine production pattern of Th1 and Th2 cells is not due to a direct differentiation-inducing effect of immunoregulatory cytokines, but rather to secondary selective mechanisms. Particular combinations of cytokines induce a predominant generation of T cell clones with anomalous patterns of cytokine production (e.g., IFN-gamma and IL-4 or IFN-gamma and IL-10) that can also be found in a proportion of fresh peripheral blood T cells with "memory" phenotype or clones generated from them and that may identify novel Th subsets with immunoregulatory functions.     

Induction of lymphomonocyte activation by HIV-1 glycoprotein gp120. Possible role in AIDS pathogenesis

Dysfunction of cytokine secretion pattern has been suggested to play a central role in the immunopathogenesis of HIV infection. In fact a shift of T helper cell functions from a Th1-type to TH0- or TH2-type has been observed in HIV-1 infected subjects undergoing disease progression. The inhalance of cytokine network is accompanied by persistent activation of the immune system, impaired ability to mount a proper activation response (anergy), and priming to apoptosis. Extensive investigation during the last decade has been conducted on the influence of HIV-1 gp120 or of its precursor gp160 on several lymphocyte and monocyte functions. Gp120 is able to rise intracellular calcium concentration and to induce the formation of inositol triphosphate, can block mitogen- or antigen-driven T cell activation, can induce altered cytokine production by activated PBMC subpopulations, determines impaired cytotoxicity and chemotactic response to antigens, interferes with the activity of antigen presenting cells, enhances or induces apoptosis, stimulates polyclonal B cell activation and induces or up-modulates a number of cytokines, including IL-6. TNF, IL-1-alpha and -beta, IL-10 and IL-8. Furthermore, both IFN-alpha and -gamma, as well as several markers of IFN activity, such as beta 2-microglobulin and neopterin, are induced in gp120-stimulated PBMC. However, neither IL-4 (Th2-type) nor IL-2 (Th1-type), nor DNA synthesis are activated by gp120. On the other hand gp120-stimulated PBMC express increased IL-2 receptors, and can be induced by exogenous IL-2 to proliferate, suggesting that they are in a state of at least partial activation. According to this hypothesis, other activation markers, both early (such as CD69), and late (such as CD45RO and CD71), are induced by gp120, but this even partial activation does not lead to the ability of PBMC to support productive infection by HIV-1, unless in the presence of exogenous IL-2. The HIV-induced cytokines can influence HIV infection either directly, by up- or down-modulating virus replication, or indirectly, by modulating the expression of cellular molecules. In fact, during the budding process, the HIV envelope captures a number of cell membrane proteins, including cytokine receptors such as IL-2R, adhesion molecules such as LFA-1, ICAM-1, -2, HLA Class I and II, as well as cell lineage markers. Gp120-induced cytokines, particularly IFN-gamma, upmodulate the cellular expression of intercellular adhesion molecules, such as ICAM-1. We have shown that the IFN-gamma-driven increase of the expression of ICAM-1 by cells chronically infected with HIV-1 can be transmitted to the virus progeny, resulting in phenotypic alteration of the virus, and leading to the expansion of its host cell spectrum to CD4-negative cells expressing the appropriate ligands, i.e. LFA-1. Intercellular adhesion molecules are also involved in the cell-mediated transmission of HIV infection, and the increased ICAM-1 expression induced by IFN-gamma determines a stimulation of the transmission of HIV from abortively infected endothelial cells to permissive CD4 lymphocytes. On the whole, these data indicate that HIV, or its soluble products such as gp120, can modify several PBMC functions, by inducing a number of cytokines and a partial state of immune activation. It is possible that the gp120-driven changes of PBMC functions are not only an epiphenomenon of HIV infection, but rather, it is likely that they can participate in the immunopathological events responsible for disease progression.     

Human retinal pigment epithelial cell interleukin-8 and monocyte chemotactic protein-1 modulation by T-lymphocyte products

PURPOSE: The purpose of the study was to examine the effect of T-lymphocyte products on human retinal pigment epithelial (HRPE) cell interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) secretion and gene expression. METHODS: HRPE cells were stimulated for 2, 4, 8, or 24 hours with 20% conditioned media (CM) from T-lymphocytes stimulated with CD3 or CD28 monoclonal antibodies (mAbs) or phorbol myristic acid. In some experiments, CM from CD3 mAb-stimulated T-lymphocytes was preincubated with neutralizing anti-(alpha)-tumor necrosis factor (TNF), alpha-interferon-gamma (IFN-gamma), or alpha-interleukin-1 (IL-1) mAb (control) to determine the contributions of each of these cytokines to HRPE chemokine induction by stimulated T-lymphocyte CM. HRPE cells were stimulated for 8 and 24 hours with IL-1 beta (0.2 to 20.0 ng/ml) (positive control), TNF-alpha (0.2 to 20.0 ng/ml) (positive control), IFN-gamma (1 to 1000 U/ml), IFN-gamma + IL-1 beta, IFN-gamma + TNF-alpha. Interleukin-2 (IL-2; 100 ng/ml) alone or in combination with IL-1 beta, TNF-alpha, or IFN-gamma also was tested. Enzyme-linked immunosorbent assay (ELISA) and Northern blot analyses were performed to determine secreted IL-8 and MCP-1 and their steady state mRNA expression, respectively. RESULTS: ELISA showed significant increases in HRPE IL-8 and MCP-1 secretion by CM from T-lymphocytes stimulated with CD3 or CD3 + CD28 mAb. Smaller, but significant, increases in IL-8 and MCP-1 resulted from CM phorbol myristic acid-stimulated T-lymphocytes. CM preincubated with neutralizing alpha-TNF or alpha-IFN-gamma mAb induced significantly less HRPE IL-8 and MCP-1, whereas preincubation of CM with neutralizing alpha-IL-1 mAb failed to inhibit CM-induced IL-8 or MCP-1. Northern blot analysis showed increased HRPE IL-8 and MCP-1 mRNA expression within 2 hours of stimulation and was maintained up to 24 hours. CM from T-lymphocytes stimulated with CD3 mAb or CD3 + CD28 mAb produced the greatest increases in IL-8 and MCP-1 mRNA. IFN-gamma induced dose-dependent increases in HRPE MCP-1, but not IL-8, IFN-gamma potentiated IL-1 beta and TNF-alpha-induced MCP-1 production, but showed little modulation of IL-1 beta and TNF-alpha-induced IL-8 production. IL-2 did not induce HRPE IL-8 or MCP-1, nor did it modulate the effects of the other cytokines. Northern blot analysis confirmed the ELISA results. CONCLUSIONS: T-lymphocyte secretions induce HRPE IL-8 and MCP-1 gene expression and secretion. TNF and IFN-gamma appear to be necessary components of T-lymphocyte CM for the induction of HRPE IL-8 and MCP-1. IFN-gamma alone induces HRPE MCP-1, albeit to a lesser extent than would IL-1 beta or TNF-alpha, and potentiates IL-1 beta- and TNF-alpha-induced HRPE MCP-1. IL-2 does not appear to modulate cytokine-induced HRPE IL-8 or MCP-1.     

The mRNA-phenotype of granuloma formation: CD4+ T cell-associated cytokine gene expression during primary murine listeriosis

In murine listeriosis, elimination of bacteria and immunity to reinfection critically depend on Thy1+ CD4- cells, while cell-mediated inflammatory phenomena such as DTH and granuloma formation are mostly mediated by CD4+ T cells. In an attempt to correlate T cell phenotype and function with a particular set of cytokines produced, we examined the cytokine gene expression profile associated with the presence or absence of Thy1+, CD4+ and/or CD8+ cells in the livers of mice during a primary infection with L. monocytogenes. The presence of CD4+ cells was found to be closely associated with mRNA expression for IL-2, IL-3 and IL-4, a 5-fold increase in expression of TNF-alpha and GM-CSF and a 25-fold increase in expression of IFN-gamma and TNF-beta mRNAs, and temporally coincided with the development of granulomatous lesions. In vivo neutralization of TNF-alpha and, to a lesser extent, IFN-gamma resulted in abrogation of granuloma formation. A similar correlation between the presence of CD8+ cells and mRNA expression for any one of the cytokines studied did not exist, pointing to a qualitatively different mechanism of CD8+ T cell mediated cure of listeriosis.     

Demonstration of human T lymphotropic virus type I (HTLV-I) tax-specific CD8+ lymphocytes directly in peripheral blood of HTLV-I-associated myelopathy/tropical spastic paraparesis patients by intracellular cytokine detection

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an inflammatory neurologic disease caused by HTLV-I infection and has been associated with elevated levels of several proinflammatory cytokines in both serum and cerebrospinal fluid. It is unknown what kind of cells secrete these cytokines and if HTLV-I Ags are associated with this phenomenon. Here, we investigated the expression of cytokines in PBL from eight HAM/TSP patients, nine HTLV-I-infected asymptomatic carriers, and seven healthy controls by flow cytometry combined with intracellular cytokine staining. PBL were cultured with brefeldin A without mitogen and IL-2 for 14 h. Under these conditions, CD8+ cells produced proinflammatory cytokines including IFN-gamma, TNF-alpha, and IL-2, which were significantly elevated in HAM/TSP patients. The proportion of CD8+ cells producing IFN-gamma in HAM/TSP patients, asymptomatic carriers, and healthy controls were, on average, 4.9, 0.4, and 0.3%, respectively. IFN-gamma production by these CD8+ cells was suppressed by anti-HLA-class I Ab. Purified CD8+ cells from an HLA-A2 HAM/TSP patient produced IFN-gamma by cocultivation with autologous CD4 cells, the main reservoir of HTLV-I in vivo, or allogenic HLA-A2+ B cells pulsed with a known immunodominant HTLV-I tax peptide. These data suggest that high levels of circulating HTLV-I-specific CD8+ T lymphocytes have the potential to produce proinflammatory cytokines and may promote inflammatory responses to HTLV-I in HAM/TSP patients.     

Effects of sleep and circadian rhythm on human circulating immune cells

The role of nocturnal sleep for normal immune regulation and its relation to circadian rhythm was examined in 10 men participating in two 51-h sessions. One session included two regular wake-sleep cycles; the other included a night of sustained wakefulness followed by a night of recovery sleep. Blood was collected every 3 h to determine PBMC counts, including the enumeration of monocytes, NK cells, and lymphocyte subsets (CD19+, CD3+, CD4+, CD8+, HLA-DR+). Production of IL-1beta, TNF-alpha, IL-2, and IFN-gamma was determined after stimulation of whole blood samples with LPS and PHA, respectively. Concentrations of IL-6 and cortisol were assessed in plasma. Enumeration of cells indicated significant circadian rhythms for all PBMC subsets under conditions of sustained wakefulness. Compared with sustained wakefulness, nocturnal sleep acutely reduced the numbers of monocytes, NK cells, and counts of all lymphocyte subsets. However, in the afternoon and evening of the day following sleep, counts of NK cells and lymphocytes were significantly higher than after nocturnal wakefulness, indicating that effects of sleep interacted with those of the circadian pacemaker. Sleep markedly enhanced production of IL-2 by T cells (CD3+) but did not influence production of IL-1beta and TNF-alpha, or IL-6 concentrations. Effects of sleep were not mediated by changes in cortisol. The decrease in monocytes, NK cells, and lymphocytes, together with an increased production of IL-2 during sleep, may serve to support ongoing immune defense in extravascular lymphoid tissue during a time of diminished acute Ag challenge.     

Study of T-lymphocyte subsets of healthy and Mycobacterium avium subsp. paratuberculosis-infected cattle

The relative contributions of T-lymphocyte subsets to host defense in cattle infected with Mycobacterium avium subsp. paratuberculosis is reported. The subsets were purified with appropriate monoclonal antibodies and a magnetic bead column separation system, and their purity was verified by flow cytometry. Biological activity of each subset, expressed as lymphoproliferation and gamma interferon (IFN-gamma) production, was measured in response to phytohemagglutinin (PHA) and an M. avium antigen preparation (A-PPD). IFN-gamma was measured by antibody capture enzyme-linked immunosorbent assay. The results showed a correlation between proliferation and IFN-gamma production in response to A-PPD but not to PHA. In response to PHA, CD4+ lymphocytes were the most prolific producers of IFN-gamma. CD8+ lymphocytes produced IFN-gamma to a lesser extent, whereas gammadelta+ T lymphocytes produced little or no IFN-gamma. Differences observed between the amount of IFN-gamma produced by CD4+ versus CD8+ cells and CD4+ versus gammadelta+ cells were significant (P < 0.01), but those between peripheral blood mononuclear cells (PBMC) and CD4+ T cells were not. Similar responses to A-PPD were observed except that PBMC produced higher levels of IFN-gamma than did CD4+ T cells. These data for cattle are similar to observations made for other animal species, where CD4+ cells are the major type of T lymphocytes producing IFN-gamma. They further suggest that whatever the role gammadelta+ T cells may play in paratuberculosis, it is not likely to be mediated by IFN-gamma production.     

Novel delivery systems for coagulation proteins

Interferon-alpha (IFN-alpha) is an important molecule in the antiviral response, but cells from HIV-1-infected individuals show a reduced ability to secrete IFN-alpha. We investigated an association between an imbalance of type 1/type2 cytokines and the production of IFN-alpha in HIV-1 infection. We used whole blood culture to study the cytokine production profile, interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), in response to HIV-1 antigens and to study the Sendai Virus and HSV-1-induced-production of IFN-alpha in seven HIV-1-infected patients. An impaired synthesis of IFN-alpha was obtained in patients with a predominant IL-4 production (IL-4 > IFN-gamma), and we found a positive correlation between the ex vivo production of IFN-alpha and the IFN-gamma/IL-4 ratio but not with the HIV RNA copy number in plasma. We investigated the role of T-cell-derived cytokines in the in vitro production of IFN-alpha by PBMC from eight healthy donors, activated with Sendai Virus or HSV-1. Whereas type 2 cytokines (IL-4, IL-13) inhibited virus-induced IFN-alpha synthesis, on the contrary, type 1 cytokines (IL-2, IFN-gamma) enhanced it. A disarray in the T-cell-derived cytokine response may play a role in the defect of IFN-alpha production in HIV-1-infected individuals. Further investigations are needed to explore this hypothesis.     

Functional CD4+ T cell subsets defined by expression of CD45RC and NTA260 antigens and age-associated polarization in murine lupus

Using two mAb, one specific to the alternative exon 6-dependent epitope of CD45 molecules (JH6.2) and one a natural thymocytotoxic autoantibody (NTA) with an unknown reactive epitope (NTA260), we subdivided splenic CD4+ T cells from 2-month-old BALB/c mice into five phenotypically distinct subsets. CD45RC+NTA260- (S I) cells were phenotypically analogous to CD4+ T cells predominating in newborn mice and produced a significant amount of IL-2, but not so IL-4, IL-10 or IFN-gamma when stimulated with immobilized anti-CD3 mAb in vitro. They appeared to consist mainly of naive ThP cells. The CD45RC+NTA260+ (S II) subset also produced IL-2, but not other cytokines; however, the IL-2 levels produced were much higher than seen with the S I subset, thereby suggesting the predominance of further maturated ThP cells. The CD45RC-NTA260+ (S III) subset mainly produced IL-4, IL-10, IFN-gamma and less IL-2, and contained memory cells that helped the secondary antibody response to a recall antigen, and hence contained Th2 and probably a mixture of Th0 and Th1 cells. The CD45RC-NTA260- (S IV) subset was a poor responder to the immobilized anti-CD3 mAb. The CD45RCbrightNTA260dull (S V) subset consisted of a small number of cells that were phenotypically analogous to activated CD4+ T cells. While an age-associated decrease in the proportion of S I and less markedly in S II and in turn increase in S III subsets of CD4+ T cells occurred in normal BALB/c mice, autoimmune disease-prone (NZB x NZW)F1 mice showed a marked age-associated decrease in the proportion of not only S I, II but also III subsets. As aged (NZB x NZW)F1 mice carry CD4+ T helper cells for IgG anti-DNA antibody production, such age-associated polarization to the S IV subset appears to be critical in the pathogenesis of autoimmune disease in these mice.     

Derivation of herpesvirus saimiri-transformed CD8+ T cell lines with noncytotoxic anti-HIV activity

Herpesvirus saimiri (HVS), strain 488-77, was used to derive continuously growing transformed human CD8+ T cell lines that can suppress HIV replication in CD4+ cells via the production of an antiviral factor(s). Transformed CD8+ cell lines were obtained by HVS infection of peripheral blood mononuclear cells or purified CD8- T cells from HIV-infected or uninfected individuals. Suppression of primary or laboratory isolates of HIV was mediated by factor permeation of a transwell membrane or by cell-free culture supernatants. Suppressing and nonsuppressing cell lines were IL-2-dependent for good growth and showed a similar activated cell surface phenotype. The cell lines produced varying amounts of the cytokines IL-8, IL-10, TNF-alpha, TNF-beta, RANTES, MIP-1 alpha, and MIP-1 beta, but not IFN-alpha. No correlation was observed between the level of any of these cytokines and the presence or absence of antiviral activity in cell line culture supernatants. These cell lines have become an important resource for studying antiviral factors produced by CD8+ T cells from HIV-infected individuals.