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R L Modlin

Publications and source records attributed to R L Modlin.

At least 55 records · Page 3Linked to original sources
PubMed1989

Isolation and characterization of the highly immunogenic cell wall-associated protein of Mycobacterium leprae.

In a recent study, we demonstrated that certain reactivities crucial to the immune response in leprosy are due to protein associated with the cell wall peptidoglycan "core" of Mycobacterium leprae. We now describe a primary method for the isolation of a highly immunogenic, large molecular-size, cell wall protein (CW-P) complex from M. leprae, freed of soluble proteins, bound mycolates, arabinogalactan, and much of the peptidoglycan. The complex is of apparent relative molecular size 2 x 10(6) to 20 x 10(6) Da, is distinguished by a high content of Ala, Gly, Leu, Asx, and Glx, and some peptidoglycan, and represents up to 7% of the bacterial mass. It is stable to a variety of dissociation and reductive processes and, in accord with its size, is not resolvable by polyacrylamide gel electrophoresis. The mAb to the CW-P complex also react with the heat shock 65-kDa protein of M. leprae. Conversely, antibodies that recognize internal epitopes within the polypeptide chain of the heat shock protein also react with CW-P; however, antibodies that recognize the N and C termini of the 65-kDa protein fail to react with CW-P, and some anti-CW-P mAb do not recognize any of the soluble proteins of M. leprae. Alternate methods to derive the large peptidoglycan-associated protein result in lower yield and less of the associated heat shock protein, implying that the 65-kDa protein may not be crucial to the immunogenicity of the complex. In an accompanying paper, we demonstrate that T cell clones raised to CW-P also selectively recognize soluble proteins, primarily of 7-kDa and 16-kDa size. Thus, the image of the CW-P complex of M. leprae is of a few immunoreactive polypeptides in avid association with a modicum of peptidoglycan to which the 65-kDa polypeptide may be variably attached, perhaps due to involvement in assembly of the complex.

Amino Acids↗
PubMed1989

Compartmentalization of a CD4+ T lymphocyte subpopulation in tuberculous pleuritis.

The study of T lymphocytes from pleural fluid and tissue of patients with tuberculous pleuritis provides an opportunity to evaluate the human immune response to infection at the site of disease activity. Therefore, we investigated the phenotype and function of CD4+ pleural fluid cells from patients with tuberculous pleuritis. Pleural fluid was enriched with CD4+CDw29+ T lymphocytes, which are thought to represent "memory" T cells. Immunoperoxidase staining of pleural tissue confirmed the predominance of CD4+CDw29+ T lymphocytes at the site of disease activity. CD4+ subpopulations were evaluated for their ability to contribute to a cell-mediated immune response against Mycobacterium tuberculosis by assaying immune function in vitro. Pleural fluid-derived CD4+CDw29+ cells, but not CD4+CDw29- lymphocytes, proliferated vigorously and produced high levels of IFN-gamma when stimulated with purified protein derivative of M. tuberculosis. CD4+CDw29+ clones produced IFN-gamma specifically in response to purified protein derivative of M. tuberculosis but not to an irrelevant Ag, tetanus toxoid. IFN-gamma levels were markedly elevated in pleural fluid, compared to peripheral blood, suggesting production of this lymphokine in vivo at the site of tissue inflammation. The sum of these data indicate that, in tuberculous pleuritis, CD4+CDw29+ cells are concentrated at the site of disease activity, produce IFN-gamma and are likely to play an important role in the local human cell-mediated immune response to M. tuberculosis.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

CD2 expression and function in lepromatous leprosy.

Leprosy is a spectral disease in which clinical presentation is thought to be related to the host immune response. Previous investigations have suggested that selective unresponsiveness to Mycobacterium leprae in patients with lepromatous leprosy is due to the presence of M. leprae-specific T-suppressor cells. However, it has recently been suggested that CD2 modulation was the mechanism for the observed impaired immune response in lepromatous patients. Therefore, we studied the expression of CD2 and CD3 on lymphocytes in lepromatous skin lesions and peripheral blood mononuclear cells (PBMC). Using immunohistochemical techniques, we found that virtually all of the CD3+ cells in leprosy skin lesions expressed CD2. In addition, indirect immunofluorescence flow cytometry demonstrated that most CD3+ cells in the peripheral blood possessed the CD2 marker, suggesting that CD2 expression of T-lymphocytes is normal. T-cell activation using paired anti-T11(2) and anti-T11(3) or anti-CD3 monoclonal antibodies demonstrated similar 3H-thymidine incorporation and gamma interferon production in the PBMC of lepromatous patients in comparison with the PBMC of their contacts and tuberculoid patients. However, lepromatous PBMC did not proliferate or produce gamma interferon in response to M. leprae. Our data suggest not only that CD2 expression is normal on T lymphocytes in lepromatous leprosy skin lesions but also that CD2 expression in peripheral blood lymphocytes is functional in T-cell activation. Defective CD2 modulation does not appear to be the mechanism for specific unresponsiveness in lepromatous leprosy.

Antibodies, Monoclonal↗
PubMed1989

Transpleural gradient of 1,25-dihydroxyvitamin D in tuberculous pleuritis.

We used tuberculous pleuritis as a model to study the compartmentalization and potential immunoregulatory role of 1,25-dihydroxyvitamin D [1,25-(OH)2-D] in human granulomatous disease. In tuberculous pleuritis, mean concentrations of total 1,25-(OH)2-D were elevated in pleural fluid, compared to blood (67 pg/ml vs. 35 pg/ml). Concentrations of albumin, protein and 25-hydroxyvitamin D (25-OH-D) were lower in pleural fluid than blood, suggesting that accumulation of binding proteins does not explain the transpleural gradient of 1,25-(OH)2-D. The mean free 1,25-(OH)2-D concentration in pleural fluid was increased 5.3-fold over that in serum. 1,25-(OH)2-D3 inhibited PPD-induced proliferation of pleural fluid mononuclear cells, antigen-reactive lines and T lymphocyte clones derived from a single cell. Patient-derived PPD-reactive lines expressed a high-affinity intracellular binding moiety for 1,25-(OH)2-D3. Pleural fluid mononuclear cells and PPD-reactive lines did not metabolize 25-OH-D3 to 1,25-(OH)2-D3. The sum of these data suggests that concentration of 1,25-(OH)2-D in pleural fluid of tuberculosis patients is probably due to local hormone production by pleural tissue-based inflammatory cells that are not present in significant numbers in pleural fluid. Elevated concentrations of 1,25-(OH)2-D in pleural fluid may exert receptor-mediated inhibition of antigen-induced proliferation by pleural fluid lymphocytes. Inhibition of lymphocyte proliferation and lymphokine production may prevent tissue destruction from an uncontrolled inflammatory response.

Calcitriol↗
PubMed1989

Potentiation of the macrophage 25-hydroxyvitamin D-1-hydroxylation reaction by human tuberculous pleural effusion fluid.

1,25-Dihydroxyvitamin D [1,25-(OH)2D] is classically viewed as a steroid hormone of renal origin that regulates mammalian and avian mineral ion homeostasis. More recently, 1,25-(OH)2D has been shown to be produced by and act on human inflammatory cells in vitro, suggesting that the hormone may be an important modulator of the host immune response. We have recently detected high concentrations of 1,25-(OH)2D in the pleural fluid (PF) of patients with tuberculous pleuritis. Working on the hypothesis that tuberculous PF contained a soluble cytokine which stimulated 1,25-(OH)2D production by tissue (pleura)-based macrophages, we examined the potential for PF from five patients with tuberculous pleuritis to potentiate 1,25-(OH)2D synthesis by heterologous pulmonary alveolar macrophages (PAM) from patients with sarcoidosis; PAM from patients with active pulmonary sarcoidosis constitutively express a 25-hydroxyvitamin D3-1-hydroxylation reaction in vitro. We demonstrated that tuberculous PF had a concentration-dependent potentiating effect on PAM 1,25-(OH)2D synthesis. The potentiating activity was positively correlated to the interferon-gamma (IFN gamma) concentration of the PF (r = 0.98; P less than 0.01) and was inhibited by 49-89% after coincubation with anti-IFN gamma monoclonal antibody (1:20,000-1:200 dilution). These data suggest that IFN gamma may be an important peripleural regulator of macrophage 1,25-(OH)2D synthesis in patients with tuberculous pleuritis and a high pleural fluid 1,25-(OH)2D concentration.

Biological Factors↗
PubMed1989

Leprosy.

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Antibodies, Bacterial↗
PubMed1988

Learning from lesions: patterns of tissue inflammation in leprosy.

The clinical forms of leprosy constitute a spectrum that correlates closely with the degree of cell-mediated immunity. Patients with tuberculoid leprosy develop strong cell-mediated responses and have only a few, localized lesions, whereas patients with multibacillary lepromatous leprosy are specifically unresponsive to antigens of Myobacterium leprae. T cells of the CD4+ subset predominate in tuberculoid lesions, whereas CD8+ cells predominate in lepromatous lesions. Monoclonal antibodies that distinguish subpopulations of CD4+ and CD8+ cells were used to analyze the distribution of T cells infiltrating lesions across the disease spectrum. In lepromatous lesions, T cells of T-suppressor phenotype (9.3-) were the predominant CD8+ cells and suppressor/inducer cells (2H4+, Leu-8+) represented half of the CD4+ subset. In tuberculoid lesions, helper T cells (CD4+4B4+) outnumbered suppressor/inducer T cells by 14:1, compared with a ratio of 1.2:1 in peripheral blood. Analysis of the precursor frequency of antigen-reactive T cells permitted us to estimate that there was a 100-fold enrichment of T cells able to proliferate in response to M. leprae antigens in tuberculoid lesions (2/100), when compared with blood from the same patients. The methods used here to characterize the T-lymphocyte subsets and frequency of antigen-reactive T cells in leprosy may be useful in analyzing immunological reactions occurring in lesions of other inflammatory and autoimmune diseases.

Antibodies, Monoclonal↗
PubMed1988

Immunological significance of Mycobacterium leprae cell walls.

Cell walls of Mycobacterium leprae, prepared by differential solvent extraction, were shown to contain arabinogalactan, mycolates, and peptidoglycan. In addition, amino acid analysis revealed the unexpected presence of large amounts of protein that retained potent immunological reactivity. Purified cell walls stimulated proliferation of T cells from tuberculoid, but not from lepromatous leprosy, patients and elicited delayed-type hypersensitivity skin reactions in guinea pigs and patients sensitized to M. leprae. Analysis of the precursor frequency of antigen-reactive human peripheral T cells revealed that as many cells (approximately equal to 1/6000) proliferate to antigen contained in cell walls as to intact M. leprae. Sequential removal of mycolates and arabinogalactan resulted in a large peptidoglycan-protein complex that retained all the immunological activity. This immunological reactivity and the inherent protein were destroyed by proteolysis. Thus, cell wall protein is a major contributor to cell-mediated immune reactivity to this pathogenic mycobacterium.

Amino Acids↗
PubMed1988

Predictors of short-term prognosis in patients with pulmonary tuberculosis.

We evaluated 191 consecutive adults with pulmonary tuberculosis in order to develop methods to determine which patients should be initially hospitalized. Using stepwise discriminant analysis, we found the six factors that were most strongly associated with an unfavorable short-term outcome (respiratory failure or death): lymphopenia, advanced age, concomitant smear-positive extrapulmonary tuberculosis, alcoholism, a high percentage of neutrophils on the differential white blood cell count, and lack of radiographic evidence of cavitation. We derived a scoring system incorporating these variables and separated patients into high- and low-risk groups. The system was prospectively validated by applying it to a separate group of 179 patients. Lymphocyte-transformation tests in 32 patients revealed an association between clinical markers of poor prognosis and minimal lymphocyte proliferation to a heat-killed strain of Mycobacterium tuberculosis.

Adolescent↗
PubMed1988

The immunology of tuberculous pleurisy.

Tuberculous pleurisy results when a subpleural nodule discharges mycobacterial antigens into the pleural space of a hypersensitive host. The clinical syndrome is a reflection of an in situ delayed-type hypersensitivity reaction in which plasma proteins are exuded into the pleural space and T-helper cells accumulate, proliferate, and produce, and release inflammatory mediators. The immune response initially contains the local infection, but in the absence of therapy, the host is at great risk of developing tuberculosis during the next 5 years. The focal accumulation of vigorously responsive T-helper cells and activated B cells in the pleural space may prove useful in identifying mycobacterial constituents which are immunogenic and possibly candidate vaccine antigens.

Animals↗
PubMed1987

Lepromin-induced suppressor cells in lepromatous leprosy.

The presence or absence of suppressor cells in leprosy patients was investigated by measuring peripheral blood lepromin-induced suppression of the Con A response. Significant suppressor activity was measured in 15 of 15 untreated or recently treated patients with lepromatous leprosy and 3 of 5 patients with borderline lepromatous leprosy. In addition, in patients with lepromatous leprosy, suppressor cell activity was found in 10 of 14 patients that had been under treatment for more than 1 year but in only 2 of 27 patients who had active or thalidomide controlled erythema nodosum leprosum. Suppression was observed in only 5 of 29 tuberculoid leprosy patients, 1 of 6 patient contacts, and 0 of 11 normal controls. The differences between the lepromatous or borderline lepromatous group as compared with the tuberculoid group were statistically significant (P less than 0.001). Our findings confirm the presence of lepromin-triggered suppressor cells in the peripheral blood of patients with lepromatous leprosy. These suppressor cells may contribute to the selective unresponsiveness of lepromatous patients to the antigens of Mycobacterium leprae.

Concanavalin A↗
PubMed1987

Leprosy: new insight into an ancient disease.

Patients with leprosy may be classified into two clinical and histopathologic categories. At one end of the spectrum, patients with tuberculoid leprosy have few skin lesions in which organisms can rarely be identified. At the other end of the spectrum, patients with lepromatous leprosy have numerous skin lesions containing myriad bacilli. Because immunologic resistance is associated with this spectrum, the study of leprosy provides a unique opportunity to gain insight into immunoregulatory mechanisms in man. In addition, serodiagnosis to identify early cases and prevention by vaccination are areas of active research. For patient care, a network of Regional Hansen's Disease Centers has been established under the sponsorship of the National Program for Hansen's Disease, Carville, LA. Because the patients are often poor, their receipt of care and medication without cost helps to ameliorate at least one of the burdens imposed by this potentially devastating illness. The program central office may be called at 800-642-2477.

Humans↗
PubMed1987

In situ identification of activated Ta1+ T lymphocytes in human leprosy skin lesions.

Using a monoclonal antibody, anti-Ta1, that identifies antigen-activated T lymphocytes in vitro, we sought to identify activated T lymphocytes in leprosy skin lesions. Greater numbers of Ta1 positive T lymphocytes were observed in tuberculoid leprosy, lepromin skin tests, and reversal reactions as compared with lepromatous leprosy or erythema nodosum leprosum (ENL) (p less than 0.001). With a double-staining technique, we found that the majority of these activated T lymphocytes were of the helper/inducer phenotype. No differences of Ta1 positive lymphocytes were observed in the peripheral blood. The defective cell-mediated immune response in lepromatous and ENL patients correlates with, and may be related to the failure of T-helper/inducer activation or proliferation in the presence of Mycobacterium leprae.

Antibodies, Monoclonal↗
PubMed1987

Immunohistological evidence of lymphokine production and lymphocyte activation antigens in tuberculin reactions.

Evidence of lymphokine elaboration and lymphocyte activation was sought in tuberculin skin test reactions at 24 and 48, or 48 and 96 h in patients with active, culture-proven, pulmonary tuberculosis. Through the use of frozen sections, immunoperoxidase techniques and monoclonal antibodies, anti-interleukin 2 positive cells were found to constitute 0.4% to 0.6% of the dermal infiltrate, and keratinocyte Ia expression at 96 h was consistent with a marker for interferon-gamma production. Cells bearing the interleukin 2 receptor more than doubled in prevalence from 24 to 48 or 96 h but cells staining with Ta1, an antibody identifying activated lymphocytes, were 10% of the cells of the infiltrate at all three times. One-half of the cells of the infiltrate were OKM1-positive, presumably macrophages, perhaps reflecting the presence of active tuberculosis.

Antigens, Surface↗
PubMed1986

Effect of cyclosporine A in erythema nodosum leprosum.

Erythema nodosum leprosum (ENL) is a reactional state of lepromatous leprosy in which the loss of suppressor cell function, decrease in suppressor cell numbers, and increase of interleukin 2 production are observed. We reasoned that cyclosporine A (CsA), by opposing these immune responses, could suppress the ENL reaction and restore patients to the quiescent lepromatous state. We tested this hypothesis in vitro by measuring the effect of CsA on M. leprae-triggered suppressor cells. In 24 of 25 patients with ENL, suppressor cell activity was restored by CsA. The target of CsA appeared to be macrophages. These findings are significant in that they provide the first evidence for the potential efficacy of CsA in the treatment of ENL. Preliminary clinical trials indicate a beneficial therapeutic effect associated with increased T suppressor cells in lesions.

Cyclosporins↗
PubMed1986

Suppressor T lymphocytes from lepromatous leprosy skin lesions.

The immune response in leprosy forms a spectrum with lepromatous leprosy patients exhibiting specific unresponsiveness to antigens of Mycobacterium leprae. This unresponsiveness is thought to be related to the prevalence of T8-positive lymphocyte in these lepromatous lesions. To analyze the immunoregulatory function of these T8 cells, we developed simple procedures to extract lymphocytes from skin biopsy specimens of patients with leprosy. These lymphocytes were sorted for T8 and T4 positive cells, and cell lines were established by expansion with interleukin 2 (IL 2) and irradiated feeder cells. All T8 positive lines tested were positive for IL 2 receptors and HLA-DR determinants. These lines were additionally assayed for lepromin-induced suppression of the normal peripheral blood lymphocyte Con A proliferative response. Thirteen of 32 lines from six lepromatous patients showed significant suppressor activity, whereas nine lines from six tuberculoid patients and one line from normal peripheral blood failed to show suppression (p less than 0.001). Taken together, the finding of M. leprae-triggered suppressor cells within lepromatous skin lesions may in part explain the M. leprae unresponsiveness of lepromatous leprosy patients.

Antigens↗