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Biomedical subjects

J J Ellner

Publications and source records attributed to J J Ellner.

At least 109 records · Page 6Linked to original sources
PubMed1993

Screening of a cosmid library of Mycobacterium bovis BCG in Mycobacterium smegmatis for novel T-cell stimulatory antigens.

We have developed a novel method for screening a Mycobacterium bovis (BCG) cosmid library in Mycobacterium smegmatis for the detection of immunostimulatory T-cell antigens (Ag). Distinctive protein banding patterns were demonstrated in culture filtrates of three of 30 recombinant M. smegmatis clones: pBCCS13 (41 and 73 kDa); pBCCS221 (30, 50 and 68 kDa); pBCCS223 (100 kDa). Western immunoblots indicated that monoclonal antibodies (mAb) directed to the previously characterized 19-, 30-, 38-, 65- and 71-kDa mycobacterial Ag were not reactive with the distinctive recombinant proteins. Furthermore, T-cell Western blots demonstrated that fractions containing the distinctive proteins were immunostimulatory. A given tuberculin-positive donor expressed unique patterns of blastogenic reactivity to protein fractions isolated from each of the three recombinant clones. Restriction enzyme digests of the three recombinant BCG inserts revealed distinctive DNA-banding patterns. The immunostimulatory Ag, therefore, are most likely encoded within different regions of the BCG genome, as contained within three distinct inserts. T-cell Western blots further indicated a heterogeneity in the repertoire of BCG-responsive T cells since tuberculin-positive donors varied in the pattern of reactivity to protein fractions isolated from the same recombinant filtrate. Most likely, immunity to M. tuberculosis results from activation of a heterogeneous array of T cells targeted to multiple immunostimulatory Ag. The method we describe should greatly enhance our ability to define the full spectrum of T-cell Ag encoded by mycobacteria, particularly those which are secreted proteins.

Antigens, Bacterial↗
PubMed1993

Mycobacterium avium complex infection and AIDS: advances in theory and practice.

The role of disseminated infection with the Mycobacterium avium complex (MAC) in the natural history of AIDS has been controversial. It is now clear that this complication of immunosuppression induced by human immunodeficiency virus type 1 (HIV-1) has a major impact upon the quality of life and duration of survival of patients with advanced HIV-1 infection. Progress has been made in our understanding of the bacteriology, pathogenesis, prevention, and treatment of MAC infection. Drs. Constance Benson and Jerrold Ellner (of Rush Medical College in Chicago and Case Western Reserve University in Cleveland, respectively) have led the effort by the AIDS Clinical Trials Group to develop new methods of managing this serious complication of advanced HIV-1 infection. In this AIDS commentary they review our current knowledge of MAC organisms and the clinical problems resulting from infection with these mycobacteria.

AIDS-Related Opportunistic Infections↗
PubMed1993

Influence of tuberculosis on human immunodeficiency virus (HIV-1): enhanced cytokine expression and elevated beta 2-microglobulin in HIV-1-associated tuberculosis.

Tuberculosis results in activation of T cells and macrophages that may harbor latent human immunodeficiency virus (HIV-1). Although such activation is beneficial to the host in terms of mycobacterial disease, it may be deleterious in terms of HIV-1. In Ugandan HIV-1-seropositive patients with pulmonary tuberculosis, antigen-induced blastogenesis and production of tumor necrosis factor-alpha (a cytokine that induces expression of HIV-1 in latently infected cells) were 3-10 times greater than in controls. The mean serum beta 2-microglobulin level was 5.22 mg/L in recently diagnosed patients, significantly greater than levels in HIV-negative patients with tuberculosis or asymptomatic HIV-1-seropositive subjects. beta 2-microglobulin was significantly lower in subjects who had completed at least 2 months of antituberculous therapy. These observations suggest that HIV-1-associated tuberculosis is accompanied by immune activation that may result in increased HIV expression and accelerated progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Tuberculosis symposium: emerging problems and promise.

Between 1985 and 1991, 39,000 cases of tuberculosis occurred in excess of those expected based on previous trends. Immigration from high-prevalence countries, coinfection with human immunodeficiency virus (HIV), and outbreaks in congregative facilities are most responsible for the increase. Coincident with the increase in tuberculosis, outbreaks of multidrug resistant (MDR) tuberculosis have occurred. Clinical and epidemiologic data support nosocomial transmission. MDR tuberculosis occurred late in the course of HIV infection and was refractory to treatment. Compounding the problems of rising incidence and increasing resistance was the sudden recognition of shortages of antituberculous drugs. The problems currently posed by tuberculosis require new approaches to diagnosis and rapid sensitivity testing as well as assuring an adequate supply of licensed drugs and development of new drugs. A number of steps have been taken by governmental agencies to assure that the challenge is met.

Drug Resistance, Microbial↗
PubMed1993

Anti-Mycobacterium avium activity of quinolones: in vitro activities.

The MICs of 88 quinolones against 14 selected reference and clinical strains of Mycobacterium avium-M. intracellular complex were determined. Agents tested included ciprofloxacin, sparfloxacin (PD 131501), and 86 other experimental quinolones. Test strains were selected to represent various susceptibilities to ciprofloxacin and other drug resistance profiles. MICs were determined by the microdilution method in 7HSF broth, with incubation for 14 days at 35 degrees C. The results showed 25 of the quinolones to be active against the strains, with MICs for 90% of the strains (MIC90s) of 2 to 32 micrograms/ml. Ten of these compounds had activities equivalent to or greater than that of ciprofloxacin. The most active compound was PD 125354, with an MIC50 of 0.5 micrograms/ml and an MIC90 of 2 micrograms/ml; comparable values for ciprofloxacin were 4 and 8 micrograms/ml, respectively. The next most active compounds, with MIC90s of 4 micrograms/ml, were sparfloxacin (PD 131501), PD 123982, PD 135144, and PD 119421. MIC90s of PD 131575, PD 126889, PD 122642, PD 139586, and PD 143289 were 8 micrograms/ml. Further evaluation of the most active agents is warranted, as is assessment of structure-activity relationships of active and inactive agents to elucidate the active portions of the compounds and to lead to the development of compounds with enhanced activity.

Anti-Infective Agents↗
PubMed1993

Anti-Mycobacterium avium activity of quinolones: structure-activity relationship studies.

The structures and inhibitory activities of 88 quinolones, previously studied as potential in vitro inhibitors of 14 selected strains of Mycobacterium avium complex, were examined in an effort to identify a quinolone with optimal activity towards all strains. A MULTICASE structure-activity relationship analysis of the inhibitory activities of these 88 quinolones against 14 strains of M. avium was performed and led to the identification of a number of structural constraints required to overcome the resistance of most of the strains. Our data suggested that the increased resistance of the strains was probably not due to a specific resistance mechanism but rather due to gradual limitation of the constraints imposed on the structure of the quinolones. This increasing structural selectivity could be produced either at the level of cell membrane penetration or at the level of interaction with the DNA gyrase receptor site. On the basis of these findings, a number of new quinolones holding the promise of superior activity are currently being evaluated in vitro and in vivo to determine the clinical relevance of our observations.

4-Quinolones↗
PubMed1993

Inhibition of growth of Mycobacterium avium in murine and human mononuclear phagocytes by migration inhibitory factor.

Infections caused by Mycobacterium avium, the most common form of diseminated bacterial disease in AIDS patients, are difficult to treat because of their resistance to many antimycobacterial drugs. The results of the present study show that recombinant migration inhibitory factor, a 12-kDa molecule recently isolated by COS-1 cell expression screening of cDNA from a human T-cell hybridoma, has potent inhibitory activity on the growth of a panel of clinical isolates of M. avium within both bone-marrow-derived murine macrophages and cultured human blood monocytes. These cells cultured in recombinant migration inhibitory factor exhibit various signs of activation, including cell division, morphological changes such as evidence of substantial phagolysosomal fusion, and enhanced secretion of tumor necrosis factor.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Accessory function and properties of monocytes from healthy elderly humans for T lymphocyte responses to mitogen and antigen.

The waning of cell-mediated immunity during aging has been attributed primarily to defects in T lymphocyte properties and functions. We assessed the potential contribution of accessory dysfunction of monocytes from the elderly on responses of T cells to phytohemagglutinin (PHA) and to tetanus toxoid after in vivo boosting. Accessory function of monocytes from the elderly subjects for T lymphocyte responses to tetanus toxoid was comparable to the young. Expression of the cytokines interleukin-1, interleukin-6 and tumor necrosis factor, the cell adhesion molecules ICAM-1 and LFA-3 and the class II major histocompatibility molecule HLA-DR by monocytes from the elderly and young subjects was similar. T lymphocytes from the elderly responded poorly to PHA. Monocytes from the elderly had a decreased accessory function for PHA-stimulated T cells from young, third donors. Thus, although many accessory properties of monocytes from the elderly are normal, the monocyte and T lymphocyte defects in the elderly for mitogen may represent interactive factors in cell-mediated immunity during aging.

Aging↗
PubMed1992

Macrophages, mycobacteria and HIV: the role of cytokines in determining mycobacterial virulence and regulating viral replication.

The marriage of two scourges, one old (mycobacterial disease) and one new (HIV), has presented an enormous challenge to the medical and public health communities, and has stirred renewed interest in mechanisms for immune control of mycobacterial infection. Virulence of both M. avium and M. tuberculosis appears to be inversely related to the capacity of the microorganisms to induce production of protective cytokines in infected hosts. TNF alpha and IFN gamma are central to this process, and mycobacterial polysaccharides may be their main determinant. Despite these similarities, M. tuberculosis and M. avium cause illnesses at the polar extremes of HIV disease. Tuberculosis, occurring early in the course of HIV disease, may promote HIV replication in otherwise latently infected cells via induction of cytokines. As such, the potential exists for accelerated progression to AIDS due to the mutual synergy of these pathogens.

AIDS-Related Opportunistic Infections↗
PubMed1992

Duration of fever during treatment of infective endocarditis.

We reviewed the duration of fever among 123 patients treated for infective endocarditis at University Hospitals of Cleveland between 1972 and 1984. One half of these patients became afebrile within 3 days after initiation of antibiotic therapy and nearly three quarters were afebrile after 1 week of therapy. After 2 weeks of therapy, nearly 90% had defervesced. Endocarditis due to Staphylococcus aureus or gram-negative bacilli, and culture-negative endocarditis, were associated with prolonged fever. Microvascular phenomena, major vessel embolization, or vegetations seen on 2-D echocardiogram also were associated with prolonged fever. Multivariate analysis revealed that only microvascular phenomena or major vessel embolization were independently associated with longer duration of fever. Endocarditis-associated mortality among patients who remained febrile after 1 week of therapy was 18%, and this was greater than the 2% mortality among patients who defervesced (p less than 0.002). These data suggest that prolonged fever during treatment of infective endocarditis is often due to tissue infarction or vascular injury. Prolonged fever also identifies patients at higher risk of a fatal outcome.

Age Factors↗
PubMed1992

Role of the mononuclear phagocyte as an antigen-presenting cell for human gamma delta T cells activated by live Mycobacterium tuberculosis.

gamma delta T cells, both human and murine, have been found to be highly responsive to mycobacterial antigens. However, the role and function of gamma delta T cells in the immune response to Mycobacterium tuberculosis remain largely unknown. In earlier studies, we demonstrated that monocytes infected with live M. tuberculosis were particularly effective inducers of human peripheral blood gamma delta T cells. The present studies were performed to further characterize the interaction between human mononuclear phagocytes, gamma delta T cells, and live M. tuberculosis, in comparison with CD4+ T cells. First, we found that resting gamma delta T cells expanded in vitro by live M. tuberculosis were specific for M. tuberculosis, and that heat killing and washing the mycobacteria removed the antigen(s) for gamma delta T cells. In contrast, the heat-killed mycobacteria retained significant antigenicity for CD4+ T cells. Second, live M. tuberculosis-expanded gamma delta T cells from healthy tuberculin-positive donors did not respond significantly to the antigens in M. tuberculosis culture filtrate, including the 65- and 71-kDa mycobacterial heat shock proteins. Third, the activation of gamma delta T cells by live mycobacteria was dependent on antigen-presenting cells, and mononuclear phagocytes were found to be very efficient antigen-presenting cells both for resting peripheral blood gamma delta T cells and for activated expanded gamma delta T cells. The mononuclear phagocyte carried the necessary costimulatory factors necessary for gamma delta T-cell proliferation. Fourth, the antigen repertoire and HLA requirements for CD4+ memory T cells and those for gamma delta T cells appear to be quite distinct from each other. CD4+ T cells recognized both soluble protein antigens and whole organisms in a class II major histocompatibility complex-restricted manner, whereas gamma delta T cells appeared to recognize only constituents associated with the whole organism and were not restricted by class I or class II major histocompatibility complex molecules. Finally, the assay system described to expand and purify responding CD4+ and gamma delta T cells after stimulation with live M. tuberculosis represented a simple approach to the direct comparison of these two T-cell populations in the interaction with mononuclear phagocytes infected with M. tuberculosis. Such studies provide insight not only into the relative roles of human CD4+ and gamma delta T cells in the human immune response to intracellular bacterial pathogens such as M. tuberculosis but also into the basic biologic role of human gamma delta T cells in antimicrobial immunity.

Antigen-Presenting Cells↗
PubMed1992

Ultraviolet-irradiated monocytes efficiently inhibit the intracellular replication of Mycobacterium avium intracellulare.

The purpose of this study was to evaluate the effect of ultraviolet (UV) radiation on the antimicrobial activities of monocytes for the intracellular pathogen Mycobacterium avium intracellulare (MAI). UV radiation augmented monocyte antimicrobial activity for MAI in a dose-dependent fashion. UVB doses of greater than or equal to 25 J/m2 resulted in a 50-100-fold reduction in MAI growth 7 d after initiation of culture. The increased monocyte antibacterial effect could be blocked by a plate glass filter, indicating that wavelengths within the UVB were responsible for the effect. UV radiation did not stimulate monocyte phagocytosis, and enhanced inhibition of MAI growth was observed in populations of adherent mononuclear cells that were devoid of T cells. This suggested that UV radiation acted directly to augment intrinsic monocyte antimicrobial activities. The administration of 8-methoxypsoralen plus UVA radiation to monocytes also augmented their antimicrobial activities against MAI. UV radiation thus may serve as a unique agent by which to evaluate the mechanisms by which mononuclear phagocytes control the growth of MAI.

Blood Bactericidal Activity↗
PubMed1992

Absence of Mycobacterium avium complex disease in patients with AIDS in Uganda.

The absence of disease due to Mycobacterium avium in Ugandan patients with AIDS, which we previously observed in a blood culture study, has been confirmed and our observations have been extended to 165 additional clinical isolates. Fourteen soil and water samples from the Ugandan environment have been cultured and revealed a high frequency of isolation of M. avium. The absence of M. avium complex disease in Uganda remains unexplained.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Bidirectional effects of cytokines on the growth of Mycobacterium avium within human monocytes.

Certain cytokines including IFN-gamma possess macrophage-activating factor activity that enhances the ability of these effector cells to destroy intracellular pathogens. A panel of recombinant and highly purified human cytokines was screened to detect this effect on the activation of human monocytes to kill Mycobacterium avium in an in vitro model. Peripheral blood monocytes obtained from 15 healthy donors were precultured for 2 days before infection. Monocytes were infected with two strains of M. avium, one AIDS-associated and relatively avirulent strain (86m2096), and the other a non-AIDS-associated isolate that demonstrated consistent and rapid growth in cultured human monocytes (LR114F). The effects of recombinant and purified human cytokines on M. avium infection were assayed by determining CFU of M. avium in lysates of infected monocytes after 0, 4, and 7 days of culture. After infection, monocytes were cultured in medium alone or continuously in the presence of the following cytokines: IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-6, IFN-gamma, granulocyte-macrophage-CSF, or macrophage-CSF. In some experiments, cultures were performed in the presence of indomethacin (IM) in addition to cytokines. Culture in the presence of rIFN-gamma was associated with a decrease in mycobacterial growth within human monocytes. The combination of 300 U/ml of IFN-gamma plus 1 micrograms/ml of IM was associated with a 10-fold decrease (p less than 0.01) in intracellular growth of the virulent strain (LR114F) compared with unstimulated cultures. No other cytokine or combination of a cytokine with IM inhibited the intracellular growth of either strain of M. avium in human monocytes. Rather, several cytokines enhanced the intracellular growth of M. avium. IL-3, IL-6, and macrophage-CSF increased the growth of one, and IL-1 alpha of both strains of M. avium tested. IL-1 alpha and IL-6 also induced M. avium growth in tissue culture medium without monocytes. These studies indicate bidirectional effects of cytokines on intracellular parasitism that may influence the outcome of M. avium infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The accessory function of B lymphocytes is resistant to the adverse effects of UV radiation.

The effect of UV radiation on the accessory activities of B lymphoblastoid cell lines (B-LCL) was investigated in three types of in vitro T lymphocyte proliferation assay, each of which differed in its accessory requirements. In contrast to monocytes whose accessory function was universally sensitive to UV radiation, B-LCL were resistant to UV in oxidative mitogenesis and staphylococcal enterotoxin B assays, in which stimulus processing was not a requirement. Expression of membrane interleukin (IL) 1 and HLA-DR antigens by B-LCL and monocytes was not affected by UV, nor was surface membrane expression of intercellular adhesion molecule-1 (ICAM-1) on B-LCL. These results were in marked contrast to monocytes in which there was a greater than 65% reduction in ICAM-1 expression. When UV-irradiated B-LCL were employed as antigen-presenting cells for tetanus toxoid-dependent T cell stimulation, a reduction in antigen-presenting function was observed. However, pulsing of B-LCL with tetanus toxoid prior to UV irradiation preserved their antigen-presenting capacity in this system also. These findings indicate that there is differential UV sensitivity among accessory cells which may be explained by different effects of UV radiation on antigen processing and adhesion molecule expression.

B-Lymphocytes↗
PubMed1991

Mycobacterium avium infection and AIDS: a therapeutic dilemma in rapid evolution.

Note from Dr. Merle A. Sande--The role of Mycobacterium avium as a pathogen in the human immunodeficiency virus-infected population has been confusing and controversial to clinicians who care for AIDS patients. The organism is commonly isolated from respiratory secretions of patients with other infections and often seems part of the resident flora; even when isolated from the bone marrow or bloodstream, its impact on the course of AIDS and contribution to systemic diseases are unknown. However, an increasing subset of patients without other documented opportunistic infections or malignancies has symptoms that respond to therapy directed against M. avium. Studies are in progress to evaluate chemotherapeutic agents. Accordingly, the subject is here reviewed and guidelines offered to infectious disease clinicians by one with a long-standing interest in mycobacterial disease who has made numerous contributions to the field.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Preservation of monocyte effector functions against Mycobacterium avium-M. intracellulare in patients with AIDS.

Mycobacterium avium-M. intracellulare is a frequent cause of late disseminated infection in patients with AIDS. The ability of human peripheral blood monocytes to phagocytose and kill M. avium was examined in an in vitro model. Monocytes were obtained from 13 healthy volunteers and 11 patients with AIDS, three of whom had documented disseminated M. avium infection. Monocytes were precultured for 2 days before infection with two AIDS-associated and two non-AIDS-associated strains of M. avium. Uptake of M. avium as measured by counting intracellular acid-fast bacilli did not differ among healthy subjects, patients with AIDS, or patients with AIDS and previously documented disseminated M. avium infection. Intracellular growth of M. avium was examined by a CFU assay of cell lysates from M. avium-infected monocytes after 0, 4, and 7 days of culture. Intracellular growth inhibition of M. avium at 7 days after infection was comparable between patients with AIDS and healthy donors for all M. avium strains tested. The effects of the addition of recombinant gamma interferon on M. avium uptake and intracellular growth in monocytes also were studied. Pretreatment of monocytes with gamma interferon prior to infection suppressed monocyte phagocytosis of M. avium. Continuously coculturing of monocytes with gamma interferon after infection augmented killing of M. avium among both patients with AIDS and healthy controls for three of the four strains of M. avium tested. The magnitude of this effect, however, was variable from donor to donor and strain to strain. No significant differences were noted between the growth-inhibiting abilities of gamma-interferon-treated monocytes obtained from healthy volunteers and those obtained from patients with AIDS.

Acquired Immunodeficiency Syndrome↗