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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytolytic capacity of mycobacterial antigen-stimulated peripheral blood mononuclear cells, from healthy Mantoux-positive volunteers and from patients with tuberculosis was investigated. Polyclonal T cell lines induced by 7 days of stimulation in vitro with PPD or a sonicate of Mycobacterium tuberculosis lysed both autologous macrophages and Epstein-Barr virus (EBV) transformed B cell lines which had been pulsed with mycobacterial antigens, to a greater extent than unpulsed target cells or target cells pulsed with an irrelevant antigen (streptokinase/streptodornase). The killing of mycobacterial antigen-pulsed macrophages and EBV-transformed B cell line targets was inhibited by monoclonal antibodies to MHC class II antigens but not by antibodies directed against MHC class I antigens. PPD-pulsed EBV-transformed lymphoblastoid cell lines (LCL) competitively inhibited the killing of mycobacterial antigen-pulsed macrophages, whereas natural killer (NK) sensitive K562 cells (with or without antigen pulsing) did not inhibit mycobacterial antigen-dependent cytolysis of macrophages. Patients with tuberculosis showed a spectrum of mycobacterial antigen-induced cytolytic capacity. Those with extensive tissue necrosis (e.g. cavitatory pulmonary tuberculosis or caseous, extrathoracic tuberculosis) had high levels while patients with disseminated (miliary) tuberculosis or disease refractory to treatment showed little evidence of mycobacterial antigen induced cytotoxicity. The ability of mycobacterial antigen-stimulated lymphoblasts to kill specific antigen-pulsed autologous macrophages was not significantly different between healthy donors and patients with tuberculosis. However, the 'mycobacterial antigen-specific' component of this cytolysis was significantly deficient (P less than 0.01) in patients. We conclude that mycobacterial antigen-specific cytotoxic T cell responses may play a significant part in the immune response to mycobacterial infection.
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PMID:Specific lysis of mycobacterial antigen-bearing macrophages by class II MHC-restricted polyclonal T cell lines in healthy donors or patients with tuberculosis. 216 2

This report describes an effective method for the cloning of Mycobacterium leprae-reactive T lymphocytes with Epstein-Barr-virus transformed autologous B cells as antigen-presenting cells. The two advantages of this method are that it drastically reduces the number of autologous peripheral blood mononuclear cells (less than 10(7) cells) needed to obtain and propagate these T-cell clones (TLC), and that it enables us to expand individual TLC to large numbers of cells (greater than 10(8)). Thus the major obstacles for the cloning of T lymphocytes--especially important with regard to patients--are bypassed. Thus far, TLC from three leprosy patients have been established. These TLC are HLA class II restricted in their M. leprae-directed response. A marked enhancement in antigen responsiveness was observed after further expansion of several TLC, some of which turned from nonresponder into responder TLC. Four tested TLC display strikingly different antigen recognition patterns when tested against a number of other mycobacterial antigens; one TLC so far recognizes only M. leprae antigens.
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PMID:HLA class-II-restricted Mycobacterium leprae-reactive T-cell clones from leprosy patients established with a minimal requirement for autologous mononuclear cells. 242 37

Human hybridomas were constructed which produce antibodies against three different extracts of Mycobacterium leprae. A thioguanine-resistant (Thgr), ouabain-resistant (Ouar), human lymphoblastoid cell line, KR-4, was hybridized with Epstein-Barr virus-transformed cell lines from lepromatous leprosy patients with fusion frequencies of greater than 10(-5). Non-Epstein-Barr virus-transformed donor cells fused at much lower rates (less than 2 X 10(-7]. Hybrids were selected in medium containing hypoxanthine aminopterin thymidine and 10(-5) M ouabain. An enzyme-linked immunosorbent assay was used to screen for antibodies against three crude extracts of armadillo-derived M. leprae, including (i) a soluble sonic extract preparation, (ii) sodium dodecyl sulfate extract of insoluble sonicated M. leprae, and (iii) a purified phenolic glycolipid antigen. Of a total of 2,200 final clones screened, 359 were found to secrete antibody which bound to soluble sonic extracts and the sodium dodecyl sulfate extract (6.7 and 9.6%, respectively), whereas 12.5% (21 out of 168) showed positivity to the glycolipid antigen. Four selected hybridomas also reacted with the deacylated derivative of M. leprae phenolic-glycolipid antigen. The specificity of these monoclonal antibodies was partially determined by screening on a panel of crude extracts from four other mycobacteria. Nine clones of 122 showed reactivity to M. leprae only. The predominant immunoglobulin was immunoglobulin M, and quantities up to 10 micrograms/ml were produced. Antibody production by hybrid clones was stable in more than 75% of the clones grown in continuous culture. By comparison, 10,000 Epstein-Barr virus-transformed lymphocyte clones from lepromatous leprosy patients were screened for anti-M. leprae antibody production, and all of the 42 clones that were initially positive in the enzyme-linked immunosorbent assay lost their antibody-producing capabilities within 6 weeks in culture. These results suggest that a combination of Epstein-Barr virus transformation and hybridization may be an optimal method in producing human monoclonal antibodies from leprosy patients.
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PMID:Human monoclonal antibodies against Mycobacterium leprae. 298 77

We have investigated whether or not Epstein-Barr virus-transformed lymphoblastoid B cell lines (EBV-BLCL) are able to present Mycobacterium leprae (M. leprae) to antigen-reactive T cell lines and clones. Such EBV-BLCL would provide us with a homogeneous and unlimited source of antigen-presenting cells. Antigen-triggered proliferation of T cells has been studied with co-cultures either with autologous or allogeneic irradiated EBV-BLCL. Our results show that EBV-BLCL are able to present M. leprae as efficiently as peripheral blood mononuclear cells, and that they also function in an HLA-DR-restricted fashion. Apart from their possible in vivo relevance, these results have important practical implications, in particular for the generation and study of M. leprae-reactive T-cell clones.
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PMID:Epstein-Barr virus-transformed B cell lines present M. leprae antigens to T cells. 300 28

The number of gamma-interferon producing cells in the peripheral blood of leprosy (LL and BT) patients and controls was studied by the reversed protein A plaque assay before and after exposure in vitro to Mycobacterium leprae bacilli and Epstein-Barr virus (EBV). The level of spontaneous gamma-interferon production was significantly higher in BT patients compared to LL patients and controls. Mycobacterium leprae induced a specific gamma-interferon response in lymphocytes from BT patients and from healthy contacts whereas in LL patients and non-exposed controls the response was low or non-existing. There were no significant differences in the gamma-interferon response to EBV between the above groups.
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PMID:A single cell assay for the study of gamma-interferon formation in leprosy patients. 304 Mar 8

Factors regulating the interaction between bone marrow haemopoietic cells, stromal elements and bone growth are poorly understood. Disturbance in the equilibrium between these elements can occur as the result of metabolic bone disease, haematologic disorders, neoplasia and infections. The present report concerns a child with myelofibrosis, hypoplastic/dyserythropoietic anaemia, osteoblast proliferation and increased bone formation. A positive tuberculin skin test and elevated EB virus titre indicated previous exposure to Mycobacterium tuberculosis and Epstein-Barr virus. No active focus of infection was identified and no improvement occurred following anti-tuberculous therapy. A dramatic improvement occurred on corticosteroid therapy. Reticulocytosis was followed by an increase in haemoglobin and platelets and a decrease in ESR. Bone marrow fibrosis resolved and the marrow was repopulated with normal haemopoietic tissue. The bone abnormalities improved both radiologically and histomorphometrically. Relapse occurred when steroids were discontinued. Bone marrow tissue culture supernate from the patient during the active phase of the disease inhibited colony formation by normal marrow mononuclear cells. This was reversed by steroid therapy. It is postulated that EB virus may have triggered osteoblast proliferation with resultant bony and haematologic changes. Response to corticosteroids could be explained on the basis of suppression of osteoblast activity and correction of fibroblast mediated suppression of haemopoiesis.
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PMID:Bone growth and haemopoiesis: steroid reversible anaemia, myelofibrosis and increased bone formation in a child. 359 56

Lymphocytic interstitial pneumonitis (LIP) is characterized by interstitial accumulation of mature lymphocytes, plasma cells, and reticuloendothelial cells and is often an unremitting process unresponsive to immunosuppressive therapy. The patient described in this report had severe candidal esophagitis and immunologic findings consistent with the acquired immune deficiency syndrome (AIDS). There was no evidence of pulmonary infection with Pneumocystis carinii, cytomegalovirus, Mycobacterium avium-intracellulare, or Cryptococcus neoformans. Open lung biopsy revealed multiple discrete nodular foci of inflammation and alveolar inflammation. The inflammatory cells were largely lymphocytes and histiocytes. Thus, LIP may be an infrequent complication of AIDS. Epstein-Barr virus and Chlamydia trachomatis are potential etiologic agents, but a specific cause remains to be identified. This disorder has been described with a higher frequency in pediatric AIDS.
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PMID:Lymphocytic interstitial pneumonia associated with the acquired immune deficiency syndrome. 400 48

A previously healthy patient with classic hemophilia who was on a home infusion program with factor VIII concentrates developed an acquired immunodeficiency syndrome manifested by a dramatic weight loss (47 kg over 12 months), lassitude, transient thrombocytopenia, and opportunistic infections with Varicella zoster, Pneumocystis carinii, and Mycobacterium avium-intracellulare. The patient was not homosexual and had no history of intravenous drug abuse. Immunologic studies showed a persistent lymphopenia with reversal of helper/suppressor-cytotoxic T-lymphocyte ratios, depression of human natural killer cell function, and in-vitro lymphocyte proliferative responses to mitogens and viral antigens. Serum IgA levels were also elevated. Serum antibodies against cytomegalovirus, herpes simplex viruses 1 and 2, Epstein-Barr virus, Varicella zoster, and hepatitis B virus were shown, suggesting previous infection by these agents. Reactivation of cytomegalovirus infection was suggested by a rising titer of antibodies against cytomegalovirus concurrent with pneumocystis pneumonia, and was confirmed by the growth of this virus in a throat culture 2 months later.
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PMID:Acquired immunodeficiency syndrome with Pneumocystis carinii pneumonia and Mycobacterium avium-intracellulare infection in a previously healthy patient with classic hemophilia. Clinical, immunologic, and virologic findings. 629 53

In 1974, an 11-year-old white boy with the X-linked lymphoproliferative syndrome developed hyper-IgM after becoming infected with Epstein-Barr virus. However, he failed to develop normal immune responses against the virus. In December 1981, when red cell aplasia occurred, he was given packed erythrocytes and gammaglobulin. Nine weeks later, acute infectious mononucleosis developed. Concurrently, his T4/T8 helper/suppressor ratio decreased from 2.7 to 0.2, and IgM antibodies to Epstein-Barr virus appeared. Subsequently, circulating B cells became undetectable in his blood, and agammaglobulinemia appeared. Red cell aplasia abated transiently. This patient's course was complicated by Haemophilus influenzae and Mycobacterium tuberculosis pneumonias, and red cell aplasia and agammaglobulinemia have persisted. Epstein-Barr virus acting as a slow virus probably induced the red cell aplasia and agammaglobulinemia because of the aberrant immune responses to Epstein-Barr virus. Immunodeficient responses to Epstein-Barr virus should be sought in other patients with the diseases documented in our patient.
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PMID:Delayed onset of infectious mononucleosis associated with acquired agammaglobulinemia and red cell aplasia. 633 Dec 39

A Burmese boy being treated with dapsone (diaminodiphenylsulfone [DDS]), 100 mg daily, for lepromatous leprosy had a fatal reaction to the drug 3 weeks after therapy was started. The clinical symptoms and progression of illness conform well to a "DDS syndrome" first described in the early 1950s. Although the syndrome clinically resembles infectious mononucleosis, neither Epstein-Barr virus nor cytomegalovirus was implicated as an etiologic agent in this case. The syndrome has been recognized during initiation of dapsone therapy for lepromatous leprosy and has led to the use of a prolonged induction period with initial dosages as low as 25 mg/week. However, because dapsone resistance has been recognized in some strains of Mycobacterium leprae, slow induction of therapy has been replaced with the schedule used for this patient. This report of a fatal reaction to dapsone emphasizes the need for caution when initiating therapy with the drug at full dosage.
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PMID:Fatal reaction to dapsone during treatment of leprosy. 723 21


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