concanavalin-a and Tuberculosis

The molecular basis of pathogen-induced host cell apoptosis is well characterized for a number of microorganisms. Mycobacterium tuberculosis is known to induce apoptosis and it was shown that live but not heat killed M. tuberculosis stimulates this biological pathway in monocytes. The dependence of this activity on live bacilli led us to hypothesize that products released or secreted by M. tuberculosis are the primary apoptotic factors for human monocytes. Thus, the culture filtrate of in vitro grown M. tuberculosis strain H37Rv was fractioned by conventional chromatography and the apoptosis-inducing activity of individual fractions was measured on human monocytes. The tests employed included measurement of cell membrane damage, caspase activation, and cytokine release. Small molecular weight RNAs of M. tuberculosis were recognized as the predominant apoptosis inducing factors. The RNA was comprised primarily of tRNA and rRNA fragments that stably accumulate in the culture filtrate during early log-phase growth. The RNA fragments signaled through a caspase-8 dependent, caspase-1 and TNF-α independent pathway that ultimately compromised the human monocytes' ability to control M. tuberculosis infection. These studies provide the first report of bacterial RNA inducing apoptosis. They also provide a foundation to pursue pathways for secretion or release of nucleic acids from M. tuberculosis and the impact of secreted RNA fragments on pathogenesis.

Topics: Apoptosis; Caspase 8; Chromatography, Affinity; Concanavalin A; Extracellular Space; Humans; Kinetics; Monocytes; Mycobacterium tuberculosis; RNA, Bacterial; Sepharose; Tuberculosis; Tumor Necrosis Factor-alpha

Mitogen- and antigen-induced interferon-gamma (IFN-gamma) responses of peripheral blood leucocytes from cervids were evaluated by a commercial whole-blood assay. The assay was applied to Mycobacterium bovis-infected white-tailed deer and reindeer, M bovis BCG-vaccinated white-tailed deer and elk, and unvaccinated, uninfected white-tailed deer, fallow deer, elk and reindeer. The responses of the M bovis-infected white-tailed deer to pokeweed mitogen (PWM) varied with time and between individuals. The responses of the M bovis-infected reindeer to PWM and M bovis purified protein derivative (PPD) were positively associated. Samples from tuberculosis-free captive herds in various parts of the USA were also evaluated. Four per cent of fallow deer, 20 per cent of elk, 44 per cent of white-tailed deer, and 91 per cent of reindeer had responses to PWM exceeding 0.25 Delta optical density, that is, PWM stimulation minus no stimulation. The specificity of the responses to M bovis PPD and a Mycobacterium tuberculosis complex-specific antigen rESAT-6:CFP-10, excluding animals not responding to PWM, ranged from 78 per cent to 100 per cent and was dependent upon the species and the positive response cut-off value. The results show that the commercial assay is valid for the detection of TB in reindeer; however, further development of the assay will be required before it is used in surveillance programmes for white-tailed deer, fallow deer, and elk.

Topics: Animals; Antigens, Bacterial; BCG Vaccine; Concanavalin A; Deer; Female; Interferon-gamma; Leukocytes; Lymphocyte Activation; Male; Mycobacterium bovis; Phytohemagglutinins; Pokeweed Mitogens; Reindeer; Tuberculosis; Vaccination

Tuberculosis due to Mycobacterium bovis in captive Cervidae was identified as an important disease in the United States in 1990 and prompted the addition of captive Cervidae to the USDA Uniform Methods and Rules for eradication of bovine tuberculosis. As well, M. bovis infection was identified in free-ranging white-tailed deer in northeast Michigan in 1995. Tuberculosis in both captive and free-ranging Cervidae represents a serious challenge to the eradication of M. bovis infection from the United States. Currently, the only approved antemortem tests for tuberculosis in Cervidae are the intradermal tuberculin skin test and the blood tuberculosis test (BTB). At present, the BTB is not available in North America. Tuberculin skin testing of Cervidae is time-consuming and involves repeated animal handling and risk of injury to animals and humans. This study evaluated the potential of a new blood-based assay for tuberculosis in Cervidae that would decrease animal handling, stress, and losses due to injury. In addition, a blood-based assay could provide a more rapid diagnosis. Twenty 6-9-month-old white-tailed deer, male and female, were experimentally inoculated by instillation of 300 colony-forming units of M. bovis in the tonsillar crypts. Seven, age-matched uninfected deer served as controls. Blood was collected on days 90, 126, 158, 180, 210, 238, 263, and 307 after inoculation and was analyzed for the production of interferon-gamma (IFN-gamma) in response to incubation with M. bovis purified protein derivative (PPDb), M. avium PPDa, pokeweed mitogen (PWM), or media alone. Production of IFN-gamma in response to PPDb was significantly greater (P < 0.05) at all time points in samples from M. bovis-infected deer as compared with uninfected control deer, whereas IFN-gamma production to PWM did not differ significantly between infected and control deer. Measurement of IFN-gamma production to PPDb may serve as a useful assay for the antemortem diagnosis of tuberculosis in Cervidae.

Topics: Animals; Concanavalin A; Deer; Enzyme-Linked Immunosorbent Assay; Female; Interferon-gamma; Male; Mycobacterium bovis; Phytohemagglutinins; Pokeweed Mitogens; Tuberculin; Tuberculosis

Peripheral blood mononuclear cells (PBMC) were obtained from culture-proven tuberculosis (TB) patients before and after 2 and 6 months of chemotherapy with a multi-drug regimen. PBMC were tested for cellular responses in antigen-induced proliferation and interferon-gamma (IFN-gamma) assays in response to complex mycobacterial antigens (whole cell Mycobacterium bovis BCG and M. tuberculosis, cell walls and short-term culture filtrate [ST-CF] of M. tuberculosis), fractionated ST-CF antigens (fractions F1-F10) and ESAT-6. The responses in TB patients before anti-TB treatment were low (median stimulation index (SI)=1-7, median delta IFN-gamma=0-12 U ml(-1), and percent responders=13-67%) to all the antigenic preparations. Following the administration of anti-TB chemotherapy for 2 months, there were significant (P<0.05) improvements in the cellular responses (median SI=9-76, median delta IFN-gamma=3-70 U ml(-1), and percent responders=33-100%) to most of the antigenic preparations tested. However, concanavalin A-induced proliferation responses of PBMC from the same patients before and after 2 months of chemotherapy were high and comparable (median SI=101 and 114, respectively, P>0.05, 100% responders). A further increase in IFN-gamma responses (median delta IFN-gamma=14-250 U ml(-1) and percent responders=43-100%) to mycobacterial antigens was observed in patients receiving chemotherapy for 6 months. Among the ST-CF fractions, F1 and F2 containing low molecular mass proteins resulted in the highest responses, whereas ESAT-6 showed responses comparable to these fractions only in a minority of the patients. HLA-DR typing of these patients showed heterogeneity in the expression of molecules encoded by HLA-DRB genes. These results show that effective chemotherapy restores cellular responses of TB patients to a large number of M. tuberculosis antigens, which could be useful in monitoring the efficacy of anti-TB treatment.

Topics: Antigens, Bacterial; Antitubercular Agents; Cell Division; Concanavalin A; Drug Therapy, Combination; HLA-DR Antigens; Humans; Interferon-gamma; Leukocytes, Mononuclear; Lymphocyte Activation; Mycobacterium; Mycobacterium bovis; Mycobacterium tuberculosis; Th1 Cells; Tuberculosis

Naturally infected cases of swine mycobacteriosis were divided into two groups, localized infection (LI) and disseminated infection (DI). Lymphoproliferative response (LPR) was then examined to estimate their immunological states. Both control and LI groups showed strong response to Concanavalin A (Con A) and phytohemagglutinin (PHA) in the LPR, and lymphocytes recovered from the LI responded well to purified protein derived from M. avium (PPD). On the other hand, the DI group showed weak response to both Con A and PHA, despite their strong response to PPD stimulation. These data suggest that the low LPR to Con A and PHA observed in the DI groups was probably not due to the general unresponsiveness of T-cells.

Topics: Animals; Concanavalin A; Lung; Lymph Nodes; Lymphocyte Activation; Mycobacterium avium; Phytohemagglutinins; Swine; Swine Diseases; Tuberculin; Tuberculosis

Given the role of cell-mediated immune responses in resistance to mycobacteria, we sought to analyse whether there was a relationship between the severity of pulmonary tuberculosis (TB) and lymphocyte proliferation as well as in vitro cytokine production. To achieve this, 25 untreated TB patients showing mild (n = 5), moderate (n = 9) or advanced (n = 11) pulmonary disease, and 12 age-matched healthy controls (mean+/-SD, 37+/-14.5 years) were studied. Peripheral blood mononuclear cells were cultured for 5 days with 10 microg/ml whole, sonicated Mycobacterium tuberculosis (WSA) or 2.5 microg/ml Concanavalin A (Con A). Supernatants were collected on day 4, from cultures grown with or without WSA, for measurement of interferon-gamma (IFN-gamma), interleukin (IL)-4, IL-1beta and transforming growth factor-beta (TGF-beta). Antigen-specific proliferation was found to be reduced among patients and more profound in those with advanced disease who also displayed a depressed response to Con A. Patients with mild TB showed a preferential production of IFN-gamma over IL-4, gave the highest level of IFN-gamma synthesis upon specific antigen stimulation and showed increased levels of IL-1beta production. Findings in patients with moderate TB appeared compatible with a mixed production of IFN-gamma and IL-4 coexisting with a higher synthesis of TGF-beta, by comparison to patients with mild TB. Advanced disease showed the highest IL-4 and TGF-beta production, with IFN-gamma synthesis readily noticeable, yet decreased in comparison with the other patient groups. Differences in cytokine response according to the amount of lung involvement suggest a role for such mediators in the immunopathogenesis underlying the distinct clinical forms of pulmonary TB, that is a predominant T helper Th)1-like or Th2-like activity in mild or in progressive TB, respectively.

Topics: Adolescent; Adult; Aged; Antigens, Bacterial; Cells, Cultured; Concanavalin A; Female; Humans; Interferon-gamma; Interleukin-1; Interleukin-4; Leukocytes, Mononuclear; Lung Diseases; Lymphocyte Activation; Male; Middle Aged; Mycobacterium tuberculosis; Severity of Illness Index; Statistics, Nonparametric; T-Lymphocytes; Transforming Growth Factor beta; Tuberculosis

The authors investigated spontaneous and induced secretion of cytokins at different stages of generalized tuberculosis. In the development of infection there were inhibited IL-2 synthesis in response to ConA, emerging activity of PNO-alpha in response to the inductors in blood serum and culture of peritoneal macrophages, enhanced secretion of IL-6. Complete immunodeficiency was associated with cessation of IL-2 synthesis by splenocytes, elevated production of IL-6 by peritoneal macrophages, low concentrations of PNO-alpha in the serum and peritoneal macrophage cultures. In the treatment of M. bovis-infected mice with antibacterial drugs alone IL-6 secretion by peritoneal macrophages and PNO-alpha activity in the serum were increased. Immunocorrection resulted in marked activation of IL-2 production by splenocytes in response to ConA as well as enhanced synthesis of IL-6 in unstimulated cultures of peritoneal macrophages.

Topics: Adjuvants, Immunologic; Animals; Antitubercular Agents; Concanavalin A; Drug Evaluation, Preclinical; Drug Therapy, Combination; Immunity, Cellular; Immunologic Deficiency Syndromes; Interleukin-2; Interleukin-6; Isoniazid; Mice; Mycobacterium bovis; Rifampin; Thymus Hormones; Tuberculosis; Tumor Necrosis Factor-alpha

An experimental mouse model of normal and deficient content of silicon in the diet in CBA strain has been developed. It is shown that after BCG vaccination silicon deficiency brought about a dramatic decrease of in vitro proliferation of splenic lymphocytes in the presence of mycobacterial antigens, ConA or in the absence of the stimuli. DTH response to tuberculin in silicon deficient mice was also reduced. The level of specific serum IgG did not depend upon silicon content in the diet. The addition of silicon into the diet of silicon-deficient mice beginning from BCG vaccination restored the level of immune reactions.

Topics: Animal Feed; Animals; Antigens, Bacterial; BCG Vaccine; Concanavalin A; In Vitro Techniques; Lymphocytes; Mice; Mice, Inbred CBA; Mycobacterium tuberculosis; Silicon; Tuberculin; Tuberculosis

The expression of interleukin-2 receptors (IL-2R) and proliferating cell nuclear antigens (PCNA) were compared for their usefulness as markers of lymphocyte activation. Heterologous polyclonal (anti-bovine IL-2R) and monoclonal (anti-human PCNA) antibodies were used to detect the expression of these molecules on activated deer lymphocytes. Both molecules were co-expressed on blast cells which had been activated with mitogen [concanavalin A (Con A)]. There was detectable up-regulation of IL-2R expression in response to antigen [Mycobacterium bovis-derived purified protein derivative (PPD)] stimulation while PCNA expression mimicked lymphocyte transformation (LT) reactivity. PCNA expression was found to more accurately reflect both antigen- and mitogen-activated lymphocyte activation, as estimated by LT activity. The expression of PCNA was used to identify antigen reactive cells from animals exposed to M. bovis. A very low percentage (1.1 +/- 0.4%) of peripheral blood lymphocytes from non-infected animals could be stimulated to express PCNA by in vitro culture with antigen (PPD). Within the infected group both diseased and healthy, 'in-contact', animals expressed significantly higher levels of PCNA upon antigen stimulation.

Topics: Animals; Concanavalin A; Deer; Kinetics; Lymphocyte Activation; Mycobacterium bovis; Nuclear Proteins; Proliferating Cell Nuclear Antigen; Receptors, Interleukin-2; T-Lymphocytes; Tuberculin; Tuberculosis

The autologous mixed lymphocyte reaction (AMLR) is an important immunoregulatory phenomenon in human immune disorders. The authors have determined the phenotype and assessed the response of malignant lymph node T-cells, from histologically and immunologically proven cases of peripheral T-cell lymphoma, in AMLR and allogeneic mixed lymphocyte reaction (MLR) and studied the secretion of lymphokines.. The proliferative response, tritiated 3H-thymidine incorporation assay, was used to determine the AMLR and allogeneic MLR of the responding T-cells. An interleukin-2 (IL-2)-dependent T-cell line (CTLL) was used for the production of IL-2 by phytohemagglutinin-stimulated T-cells in a cytotoxic assay. B-cell growth and differentiation factor activity of T-cells was studied by enzyme-linked immunosorbent assay.. The AMLR of malignant lymph node T-cells was increased characteristically in 12 of the 14 lymphoma cases studied; however, that of the blood T-cells was decreased. The allogeneic MLR of the malignant lymph node T-cells and blood-purified T-cells of the eight cases investigated was decreased. Expression or deficiency of CD2 and CD3 antigens on malignant T-cells did not show any difference in the AMLR assay.. This study demonstrates an important tendency of malignant T-cells from patients with peripheral T-cell lymphoma to proliferate in AMLR. The highly augmented AMLR but deficient allogeneic MLR observed in these malignant T-cells indicate that autologous recognitive events may play an important role in the immunopathogenesis of this human disease.

Topics: Adult; Aged; Biopsy; Concanavalin A; Female; Humans; Interleukin-2; Lymph Nodes; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Lymphoma, T-Cell, Peripheral; Male; Middle Aged; Phytohemagglutinins; T-Lymphocytes; Tuberculosis

The course of influenza and tuberculosis infections under the conditions of disturbances in the immune response of experimental animals has been studied. As revealed in the survival test, the induction of secondary T- and B-cell-mediated immunodeficiency in mice leads to an increase in the sensitivity of the body to influenza virus, especially in cases of T-cell-mediated immunodeficiency. The injection of BCG in combination with cyclophosphamide into mice induces tolerance to this antigen in the animals; this tolerance has a "split" character, i.e. it affects only T-cell-mediated, but not humoral immunity. The induction of T-cell-mediated immunodeficiency or tolerance to BCG in mice has been shown (in the survival test) to lead to the development of the sensitivity of the animals to experimental tuberculosis infection. B-cell-mediated immunodeficiency did not influence the animal survival rate.

Topics: Animals; B-Lymphocytes; BCG Vaccine; Concanavalin A; Cyclophosphamide; Immune Tolerance; Immunologic Deficiency Syndromes; Influenza A virus; Lipopolysaccharides; Male; Mice; Orthomyxoviridae Infections; Serratia marcescens; T-Lymphocytes; Tuberculosis

The profile of generation and characteristics of immunosuppressive macrophages (M phi s), which suppress the ConA-mitogenic response of spleen cells (SPCs), in host CBA/JN mice during the course of Mycobacterium avium complex (MAC) and M. tuberculosis (MT) infections were investigated. In both infections, a marked reduction in ConA mitogenic response of splenic T cells was seen around 2 weeks after infection, and this was accompanied by generation of potent immunosuppressive M phi s in the SPCs of infected mice. The suppressive activity was much stronger in MT-infected mice than in MAC-infected ones. In both infections, the large part of the suppressive M phi s exhibited suppressor activity that depended on the arachidonic acid cascade, particularly mediated by prostaglandins (PGs), and the remainder showed the suppressor action independent from PGs. The unique finding of this study is that the generation of IL-2 reactive T cell populations in SPCs in response to ConA signal was markedly inhibited by the MAC- and MT-induced immunosuppressive M phi s, whereas the suppressive M phi s failed to reduce the IL-2-producing ability of splenic T cells. In any case, the present results indicate a close similarity in immunosuppressive M phi s induced by MAC and MT infections.

Topics: Animals; Cells, Cultured; Concanavalin A; Histocompatibility Antigens Class II; Immunosuppression Therapy; Indomethacin; Interleukin-2; Macrophage Activation; Macrophages; Mice; Mycobacterium avium-intracellulare Infection; Receptors, Interleukin-2; T-Lymphocytes; Tuberculosis

The profile of generation and characteristics of splenic macrophages (M phi s) which suppress the concanavalin A (Con A) mitogenic response of splenic T cells (designated as 'immunosuppressive M phi s') in host CBA/JN mice during the course of Mycobacterium avium complex (MAC) infection were investigated. In MAC-infected mice, reductions in some cellular functions of host splenic T cells, such as the Con A mitogenic response and mixed leucocyte reaction, were seen around 2 weeks after challenge of organisms, and this was accompanied by appearance of immunosuppressive M phi s in spleen cells. In this case, increase in immunosuppressive M phi activity was seen in terms of both activity per spleen and activity per individual M phi. In this phase of the infection, MAC-induced splenic M phi s showed a markedly increased ability to produce reactive oxygen radicals in response to phorbol myristate acetate. Thus, the expression of suppressor activity of MAC-induced M phi s seems to be closely linked to their activated state. A large proportion of the immunosuppressive M phi s exhibited suppressor activity dependent on prostaglandins and membrane functions related to microfilaments. It was also found that the generation of IL-2-reactive T cell populations in response to Con A was markedly inhibited by MAC-induced splenic M phi s, whereas they caused no significant reduction in the IL-2-producing ability of normal spleen cells.

Topics: Animals; Concanavalin A; Immune Tolerance; Immunity, Cellular; Interleukin-2; Kinetics; Lymphocyte Activation; Macrophages; Male; Mice; Mice, Inbred CBA; Mycobacterium avium; Spleen; T-Lymphocytes; Tuberculosis

The results shown here demonstrate that in mice heavily infected with Mycobacterium bovis BCG Pasteur, mitogen-induced levels of interleukin-2 (IL-2) correlate temporally with the state of immunity that is being expressed in the animal during the course of the infection. Active immunity, which is conferred by populations of both CD4+ (L3T4) and CD8+ (Lyt-2) T lymphocytes, and memory immunity, which is mediated by a population of CD4+ T lymphocytes, were identified and distinguished in terms of their sensitivity to cyclophosphamide therapy, their ability to passively transfer specific resistance to infection with virulent Mycobacterium tuberculosis, and their capacity to produce and/or absorb IL-2. In this regard, concanavalin A (Con A)-stimulated L3T4+ and Lyt-2+-enriched splenocytes exhibited an apparent depression in measurable levels of IL-2 when harvested during the first 40 days of the infection, which could be explained by the subsequent observation that these T cells were capable of rapidly absorbing a known quantity of recombinant IL-2 in vitro. Detectable levels of IL-2 in these mitogen-stimulated supernatants began to rise after Day 25, which was temporally associated with a gradual shift from active immunity, to immunity mediated by cyclophosphamide-resistant memory T cells, which did not absorb IL-2 in vitro. These data indicate that fluctuations in apparent IL-2 production reflect changes in the type of immunity being expressed, rather than than some form of defect in IL-2 production.

Topics: Animals; Cell Separation; Concanavalin A; Female; Immunity, Innate; Immunization, Passive; Immunologic Memory; Interleukin-2; Lymphocyte Activation; Mice; Mycobacterium bovis; T-Lymphocytes; Tuberculosis

The response of Bcgr and Bcgs spleen cells to allogeneic Ag, mitogens, and in a system of oxidative mitogenesis using neuraminidase and galactose oxidase was investigated in two Bcg congenic systems. The Bcgr macrophages supported the MLR across H-2 barrier much better than the Bcgs macrophages. At sub-optimal or optimal doses of mitogens Bcgr mice were higher responders than their Bcgs counterparts. The superior response of Bcgr spleen cells to Con A was further investigated with the aim of identifying the population expressing this phenotype. T cells of either Bcgr or Bcgs type showed equal ability to respond to Con A in the presence of macrophages. Purified splenic macrophages from Bcgr mice contained a significantly greater percentage of Ia+-bearing macrophages compared to Bcgs mice. Splenic macrophages of the Bcgr type were more efficient than their Bcgs counterparts at restoring the Con A response of accessory cell-depleted spleen cells. Resident peritoneal macrophages as well as splenic dendritic cells from Bcgr and Bcgs mice were equally efficient at restoring this response. Glutaraldehyde-fixed Bcgr splenic macrophages were shown to be more efficient than the Bcgs cells at replenishing the response of Con A-unresponsive spleen cells when supplemented with IL-1.

Topics: Animals; Concanavalin A; Histocompatibility Antigens Class II; Immunity, Innate; Isoantigens; Leukocyte Count; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Macrophages; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mitogens; Oxygen Consumption; Phytohemagglutinins; Spleen; T-Lymphocytes; Tuberculosis

The effects of prolactin on lactation and reproductive organs are well known. However, the other possible target organs and physiological consequences of altered levels of circulating prolactin remain poorly understood. In this study, mice were treated with bromocryptine, a dopamine receptor agonist that inhibits pituitary prolactin secretion. Bromocryptine treatment prevented T-cell-dependent induction of macrophage tumoricidal activity after the intraperitoneal injection of Listeria monocytogenes or Mycobacterium bovis. Coincident treatment with ovine prolactin reversed this effect. Of the multiple events leading to macrophage activation in vivo, the production by T-lymphocytes of gamma-interferon was the most impaired in bromocryptine-treated mice. Lymphocyte proliferation after stimulation with mitogens in vitro was also depressed in spleens of bromocryptine-treated mice, and coadministration of prolactin also reversed this effect. Bromocryptine treatment also reduced the number of deaths resulting from inoculation of mice with Listeria; exogenous prolactin significantly reversed this effect. The critical influence of pituitary prolactin release on maintenance of lymphocyte function and on lymphokine-dependent macrophage activation suggests that, in mice, lymphocytes are an important target tissue for circulating prolactin.

Topics: Animals; B-Lymphocytes; Bromocriptine; Concanavalin A; Hypopituitarism; Interferon-gamma; Lipopolysaccharides; Listeriosis; Lymphocyte Activation; Lymphokines; Macrophage Activation; Macrophage-Activating Factors; Macrophages; Male; Mice; Mice, Inbred C3H; Mycobacterium bovis; Prolactin; Salmonella; Spleen; T-Lymphocytes; Tuberculosis

In the course of experimental BCG infection in mice, cytotoxic autoantibodies (CAA) of IgM class reacting with thymocytes and T lymphocytes were found. CAA were not cytotoxic for bone marrow cells and B lymphocytes. CAA reacts with PNA+, glass wool-adherent, hydrocortisone-sensitive thymocytes. The reaction of thymocytes with CAA and complement, prevented suppressor cell induction from such treated cells. The importance of CAA in mycobacterial infection is discussed.

Topics: Animals; Autoantibodies; Concanavalin A; Cytotoxicity, Immunologic; Epitopes; Immunoglobulin M; Mice; Mice, Inbred Strains; Rodent Diseases; T-Lymphocytes; Tuberculosis

Lymphocytes from peripheral blood were isolated from leprosy patients and healthy contacts (HC) of leprosy patients and stimulated in vitro with: Mycobacterium leprae and a M. leprae cell wall antigen, MLW 1; tuberculin purified protein derivative (PPD); antigens prepared from Candida albicans, Entamoeba histolytica, Leishmania aethiopica, and parotitis virus; the non-specific mitogens phytohemagglutinin (PHA) and concanavalin A (Con-A). Lymphocytes from patients with untreated lepromatous leprosy failed to respond to the M. leprae antigens, and the median response to PPD was also significantly (p less than 0.005) lower than in the HC group. They responded almost as well as the other groups to non-mycobacterial antigens, PHA, and Con-A. In LL patients who had been treated with dapsone for several (median 10) years, the failure to respond to M. leprae antigens remained, but the depression of the PPD response and the slight non-specific depression of the lymphocyte stimulation test (LST) responsiveness had been reversed. Our results confirm that the major defect in the cell-mediated immune response of LL patients is M. leprae-specific and permanent. The possibility that the defect may be due to a continuous, antigen-induced suppression of the immune response is discussed. That the defect also affected the response to PPD is important since it points to a clear antigenic relationship between M. leprae and BCG/M. tuberculosis. Evidence is presented suggesting that an antigen induced suppressor mechanism may be operating in vitro with cells from patients with borderline tuberculoid leprosy.

Topics: Adolescent; Adult; Aged; Antigens, Bacterial; Concanavalin A; Dapsone; Female; Humans; Immunity, Cellular; In Vitro Techniques; Leprosy; Lymphocyte Activation; Male; Middle Aged; Mycobacterium leprae; Phytohemagglutinins; Tuberculin; Tuberculosis

The effect of granulomatous infections upon the activity of a T lymphocyte subclass in human peripheral blood that can be induced by concanavalin A (Con A) to function in a suppressor mode was studied. Peripheral blood lymphocytes (PBL) from eleven patients with disseminated mycotic or mycobacterial infections or from controls were preincubated with and without Con A, washed and cultured with allogeneic PBL freshly drawn from healthy donors sensitive to histoplasmin. DNA synthesis was then measured in co-cultures stimulated by Con A, histoplasmin, or by the mixed lymphocyte culture (MLC) reaction alone. As compared with cells preincubated without Con A, the Con A-pretreated cells were significantly less effective in suppressing the responses of normal PBL to histoplasmin (P < 0.01), and in a one-way MLC reaction (P < 0.05). The Con A-induced suppressor activity of PBL from nine patients with localized granulomatous infections did not differ significantly from that exerted by PBL of normal controls in two of the three co-culture systems employed. These studies suggest that either dysfunction or a reduction of the Con A-inducible T-suppressor cell subpopulation in peripheral blood is frequent among patients was disseminated granulomatous infections.

Topics: Adolescent; Adult; Aged; Blastomycosis; Concanavalin A; Histoplasmin; Histoplasmosis; Humans; Hypersensitivity, Delayed; Leprosy; Leukocyte Count; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Male; Middle Aged; Skin Tests; T-Lymphocytes, Regulatory; Tuberculosis

Lymphocyte transformation tests using phytohaemagglutinin and concanavalin A showed that both T and B lymphocytes are functional in tuberculous badgers. Dose response curves indicated that purified protein derivative sensitised lymphocytes were suppressed when cultured in the presence of the antigen.

Topics: Animals; Carnivora; Concanavalin A; Lymphocyte Activation; Mycobacterium bovis; Phytohemagglutinins; Tuberculin; Tuberculosis