T cell responses to Mycobacterium bovis in red deer, a large animal model for tuberculosis

Uterine morphology assessed by transvaginal ultrasound and the hemodynamics of intratumoral vessels assessed by color Doppler ultrasound were prospectively correlated with the clinical outcome of 25 patients with trophoblastic tumors. Twenty patients were followed without treatment (observation group) and 16 achieved complete local resolution. The four subjects with local persistence were combined with five patients referred from other institutions and received chemotherapy (treatment group). In the observation group both techniques had 100% accuracy in predicting local resolution or local persistence. Persistence was predicted 1-3 weeks before the increase of beta-human chorionic gonadotropin (beta-hCG) levels, whereas resolution was observed up to 8 weeks before the disappearance of beta-hCG. In one patient normal uterine morphology and vascularization in the presence of elevated hCG levels was associated with extrauterine spread. In the treatment group, normal uterine ultrasound morphology and negative color Doppler results had 100% negative predictive value. False-positive results were observed in two cases. We conclude that ultrasound evidence of abnormal uterine morphology or persistent vascularization on color Doppler examination with persistent hCG levels is indicative of local persistence. Normal uterine morphology with negative color Doppler results may be associated with extrauterine spread.     

IL-6 produced by macrophages infected with Mycobacterium species suppresses T cell responses

The ability of Mycobacterium bovis Calmette-Guérin bacillus-infected bone marrow-derived macrophages to process and present exogenously added Ags to T cells and stimulate their growth and production of IL-2 was examined. The infected macrophages were inhibited in their ability to activate T cells, and this inhibition could be transferred to uninfected macrophages with filtered supernatants from mycobacteria-infected macrophages. The inhibition was not due to decreases in macrophage viability, Ag uptake, or cell surface expression of MHC class II or other accessory molecules necessary for Ag presentation. Other intracellular pathogens such as Listeria monocytogenes and Leishmania mexicana did not induce the soluble inhibitory factor, while Mycobacterium avium strain 101 did, suggesting the factor is specific to infection with mycobacteria. The inhibitory effect was reversed completely by preincubation with neutralizing Abs against IL-6, and rIL-6 partially restored the effect. Approximately 10,000-fold more IL-6 was produced by mycobacteria-infected macrophages compared with uninfected controls. Such sustained levels of IL-6 may account for the immune unresponsiveness apparent in both human and murine mycobacterial disease.     

CD4+ alpha beta T cell and gamma delta T cell responses to BCG in patients with pulmonary tuberculosis--comparison with healthy controls

PURPOSE: We evaluated retrospectively the socioeconomic development of epilepsy patients after temporal or extratemporal epilepsy surgery and analyzed the relationship to clinical and neuropsychological data. METHODS: 151 patients (from ages 11-65 years; mean postoperative followup: 3 years) replied to a structured questionnaire, which referred to objective data of the patient's educational and vocational development. Neuropsychological data were obtained from pre- and postoperative (1-year follow-up) examinations. RESULTS: The preoperative development data indicated that patients exposed to epilepsy at any developmental stage had a higher prevalence of educational/vocational difficulties as compared with patients with a later onset of epilepsy. Postoperatively, the integration of the formerly unemployed improved and the unemployment rate decreased from 33 to 16%. Out of those patients who had been schooled or who were employed, 79%-91% made progress in development, or were at least able to keep their status. Only 2 of 14 patients, who had been retired early because of their epilepsy, returned to employment. In general, a deterioration of the socioeconomic status was significantly related to insufficient seizure control. A reemployment of patients who were formerly unemployed depended mainly on age and neuropsychological outcome. CONCLUSIONS: Our results suggest that early and successful surgical intervention improves or at least maintains the socioeconomic situation, especially the employment status.     

Identification and characterization of autoreactive T cell responses to bullous pemphigoid antigen 2 in patients and healthy controls

Antibodies against the extracellular domain of bullous pemphigoid antigen 2 (BPAG2) are thought to play a key role in the pathogenesis of bullous pemphigoid (BP), the most frequent autoimmune bullous disease of the skin. Autoreactive T cell responses to BPAG2 were investigated in 16 BP patients and 24 healthy controls by coculture of PBMC with two recombinant BPAG2 proteins (extracellular domain of BPAG2). Primary in vitro T cell responses to BPAG2 were observed in 10/12 BP patients expressing the BP-associated HLA-DQB1*0301 allele and 8/10 DQB1*0301 positive healthy individuals. DQB1*0301 also restricted three autoreactive T cell lines from two BP patients and a healthy donor. In contrast, PBMC from 14 normal patients carrying HLA class II alleles other than DQB1*0301 were not stimulated by BPAG2. Autoreactive BPAG2-specific CD4(+) T cell lines and clones from five BP patients produced both Th1 and Th2 cytokines, whereas three autoreactive T cell lines from three DQB1*0301 positive normal patients produced exclusively IFN-gamma. The absence of BPAG2-specific Th2 cells in healthy individuals strongly suggests that autoreactive Th2 responses to BPAG2 are restricted to BP patients and may thus be critical in the pathogenesis of BP.     

Delayed-type hypersensitivity responses to ESAT-6 and MPT64 from Mycobacterium tuberculosis in the guinea pig

Two antigens from Mycobacterium tuberculosis, ESAT-6 and MPT64, elicited delayed-type hypersensitivity (DTH) skin responses in outbred guinea pigs infected with M. tuberculosis by the aerosol and intravenous routes but not those sensitized with M. bovis BCG or M. avium. The DTH epitope of ESAT-6 was mapped to the C terminus. Nonresponders to the individual antigens were found, but all animals responded to a combination of ESAT-6 and MPT64 or their respective minimal target peptides. Correspondingly, these molecules could form the basis of a new skin test for tuberculosis.     

Mycobacterium tuberculosis reactive T cell clones from naturally converted PPD-positive healthy subjects: recognition of the M. tuberculosis 16-kDa antigen

The methods of spatial statistics were applied to assess the geographical pattern of risk of Lyme borreliosis in Central Bohemia, the Czech Republic, based on retrospective data on disease contractions. The statistical risk was then compared at 15 selected localities with the infection challenge presented by ticks and insects carrying borreliae. Over 5,000 Ixodes ricinus (L.) ticks and 390 haematophagous dipterans were screened by direct immunofluorescence method, and the spatial and seasonal variance of infection rates were studied. Infected ticks were found at each locality throughout the warm season; in nymphs, sample infection rates ranged from 4.9% to 23.1% with a mean of 14.5% in spring, from 7.7% to 28.7% with a mean of 16.1% in summer, and from 7% to 20.6% with a mean of 13.6% in autumn. The statistical risk was found to correlate well with an average nymphal infection challenge, i.e. I. ricinus nymphal abundance x infection rate, at a given locality. Statistically significant cumulation of insect-history recalling patients into several, generally wetland, areas was ascertained; borreliae were revealed in 0.5% of the dipterans examined.     

Distribution of antibody titres against phenolic glycolipids from Mycobacterium tuberculosis in the sera from tuberculosis patients and healthy controls

We have shown that the cytotoxic response of TNF-sensitive L929 cells and TNF-resistant EMT-6 cells to TNF-alpha can be modulated by ADP-ribosylation inhibitors independently of ADP-ribosylation rates. To explore the possibility that these inhibitors modulate TNF cytotoxicity by interfering with cellular protective mechanisms, we evaluated their effects on general RNA synthesis and on mRNA expression of two proposed protective genes, manganous superoxide dismutase (MnSOD) and heat shock protein 70 (hsp70). We found that ADP-ribosylation inhibitors could inhibit general RNA synthesis in a dose-dependent fashion to a similar extent in both EMT-6 and L929 cells, although these inhibitors increased or decreased the sensitivity of the cells to TNF, respectively. In EMT-6 cells, combination of actinomycin D with these inhibitors further inhibited the RNA synthesis rate, and it actually decreased the TNF sensitivity of the EMT-6 cells. Furthermore, the expression of MnSOD or hsp70 was not regulated by these inhibitors. Thus, TNF resistance must depend on other mechanisms in addition to the expression of these protective genes.     

T cell cytokine responses in persons with tuberculosis and human immunodeficiency virus infection

Tuberculosis causes more extensive and life-threatening disease in patients with HIV infection than in immunocompetent persons. To investigate the hypothesis that these severe manifestations of tuberculosis may be due to alterations in cytokine production, we evaluated cytokine patterns in HIV-infected tuberculosis patients. Upon stimulation with Mycobacterium tuberculosis in vitro, PBMC from HIV-infected tuberculosis patients had reduced proliferative and type 1 responses, compared with HIV-seronegative tuberculosis patients. The reduction in proliferative responses was independent of the CD4 cell count, but the reduced type 1 response was a direct result of CD4 cell depletion. There was no enhancement of type 2 cytokine production in HIV-infected patients, although production of IL-10 was prominent in all tuberculosis patients. In HIV-infected tuberculosis patients, M. tuberculosis-induced proliferative responses were significantly enhanced by neutralizing antibodies to IL-10 but not by antibodies to IL-4 or by recombinant IL-12. The M. tuberculosis-induced type 1 response was augmented both by antibodies to IL-10 and by recombinant IL-12. Tuberculosis in the context of HIV infection is characterized by diminished type 1 responses, probably induced by immunosuppressive cytokines produced by macrophages/monocytes, rather than by type 2 cells.     

Two-dimensional electrophoretic analysis of humoral responses to culture filtrate of Mycobacterium bovis BCG in patients with leprosy and tuberculosis

Various aspects of our communication are well known to have changed over time (1-3). This article describes a cross-sectional study that examined the acoustic characteristics of two groups of Australian women aged 18-25 years from recordings made in 1945 and 1993 and investigated the possible changes in the voice across generations. Archival recordings from 1945 which had been used in a longitudinal study (4) were compared to recordings made in 1993. The results of this study show that women in 1993 have significantly deeper voices than women of the same age recorded in 1945. The possible factors influencing this change are discussed.     

Delineation of human antibody responses to culture filtrate antigens of Mycobacterium tuberculosis

This study was undertaken to define the antigens in culture filtrates of actively replicating Mycobacterium tuberculosis that are recognized by antibodies from tuberculosis (TB) patients. Two-dimensional Western blots were probed with sera from healthy controls and TB patients that were preabsorbed with Escherichia coli lysates to deplete cross-reactive antibodies. Antibodies from TB patients recognized 26 of the >100 culture filtrate proteins, and the repertoire changed with disease progression. Only 12 of 26 antigens, including 3 proteins implicated in colonization and invasion by mycobacteria (MPT51, MPT32, and 85C), and 9 (as yet undefined proteins) were reactive with sera from TB patients with early noncavitary or cavitary disease. Eight additional antigens, including 4 undefined proteins, were recognized only by sera from a subset of patients with advanced cavitary disease. Studies suggest that 3 of the antigens recognized by sera from patients with early TB (85C, MPT32, and a 88-kDa protein) have strong serodiagnostic potential.     

B cell responses to a peptide epitope: III. Differential T helper cell thresholds in recruitment of B cell fine specificities

Th cell requirements in the individual stages comprising a murine humoral response to a synthetic peptide were examined. Induction of a T-dependent IgM response was readily achieved in the presence of unprimed or low numbers of Ag-primed T cells. In contrast, class switch to the IgG isotype of Abs demanded a markedly elevated frequency of primed T cells and occurred concomitantly with B cell differentiation into an membrane-bound IgG+ memory population. These results indicated that induction and progression of a T-dependent humoral IgG response were comprised of a single rate-limiting step represented by that involving Ab isotype switch. Subsequent studies established that this also represented the principal step where antibody-purifying mechanisms operate. This was enforced by imposing a threshold barrier for Th cell recruitment by early Ag-activated B cells to enable class switch and consequent retention as the response progresses. The quantum of this threshold, however, was not invariant, but, rather, was described as a balance between the affinity of B cell receptor for Ag and the frequency of Ag-specific Th cells.     

Differential responses to challenge with live and dead Mycobacterium bovis Bacillus Calmette-Guérin

Bacillus Calmette-Guérin (BCG) vaccination has been shown to protect against challenge with virulent Mycobacterium tuberculosis in a range of experimental animal models: in each case, protective efficacy requires vaccination with live bacteria. With the goal of moving to a new generation of safer, nonliving vaccines, efforts have been made to identify the factors that determine the efficacy of live vaccination. We show that injection of live, but not dead, BCG induces localized swelling in the mouse footpad model. Live and dead bacteria induce similar responses during the first week after vaccination as determined by immunohistochemical analysis of the site of injection and of the draining lymph node. The subsequent differential response is characterized by migration of acid-fast bacilli to the draining lymph node in the case of the live vaccine. This is accompanied by an increase in mononuclear cells in the lymph node and by expression of inducible nitric oxide synthase (iNOS) both in the lymph node and at the site of injection. The ability of the bacteria to migrate to the lymph node may be an important element in the efficacy of live BCG vaccination.     

Helper and cytotoxic T lymphocyte responses to influenza vaccination in healthy compared to diabetic elderly

This study was designed to determine the effect of Type II diabetes mellitus in older adults on two measures of the cell-mediated immune response to influenza vaccination. Twenty-two elderly persons with diabetes mellitus were compared to 20 healthy seniors, all of whom were living independently in the community. Peripheral blood mononuclear cells (PBMC) were challenged in vitro with live influenza virus, pre-vaccination and 4 and 12 weeks post-vaccination. PBMC culture supernatants were assayed for IL-2 activity as a measure of the helper T-cell response to vaccination. The cytotoxic T-lymphocyte response was determined using an assay of granzyme B activity in PBMC lysates. Initial analysis of the data showed increased IL-2 production in post-vaccination PBMC cultures from the diabetic group compared to the healthy group. However, when vaccination histories were used in an analysis of variance, it was found that the difference between the two groups was related to vaccination history. Study subjects vaccinated one year prior to participation in this study compared to those who had not been previously vaccinated, demonstrated a significantly suppressed IL-2 response to vaccination. Type II diabetes mellitus had no effect on the IL-2 response to vaccination. The granzyme B response to vaccination was not significantly affected by previous vaccination and results were similar for the healthy and diabetic elderly groups.     

Tuberculosis cutis miliaris disseminata due to multidrug-resistant Mycobacterium tuberculosis in AIDS patients

Two patients with AIDS and disseminated tuberculosis characterized by cutaneous involvement are reported. They developed a maculopapular skin eruption, from which a multidrug-resistant Mycobacterium tuberculosis strain was isolated. In both cases the clinical course was rapidly fatal. Tuberculosis cutis miliaris disseminata should be differentiated from the skin lesions frequently seen in HIV-infected patients, especially from folliculitis. In patients with tuberculosis, the appearance of cutaneous lesions may be due to the haematogenous dissemination of mycobacteria. Therefore, early identification of the causative organism by use of optimal microbiological methods is fundamental.     

Mycobacterium avium complex and Mycobacterium tuberculosis in patients infected with the human immunodeficiency virus

Primary care physicians play an important role in identifying and treating bacterial infections in adults infected with the human immunodeficiency virus (HIV). Mycobacterium avium complex and Mycobacterium tuberculosis are pathogens that can cause systemic or local infection in these patients. We review the epidemiology, pathogenesis, clinical presentation, and principles of treatment for these two mycobacterial pathogens. Because M tuberculosis disease is preventable and curable and yet communicable, physicians should maintain a high degree of suspicion for tuberculosis in HIV-infected adults. In comparison, the goal of treating M avium complex in patients with advanced HIV disease is to reduce constitutional symptoms and improve survival.     

Bovine T cell responses to Cryptosporidium parvum infection

To better understand the immune mechanisms important for clearing of the primary infection and the subsequent development of resistance to Cryptosporidium parvum infection, several groups have recently characterised changes within the lymphoid cell population of the intestinal mucosa and associated lymphoid tissue in calves with cryptosporidiosis. In naive animals, infection results in a significant increase in the number of CD4+ and CD8+ T cells present within the intraepithelial lymphocyte population, lamina propria and Peyer's patch of the ileum. This is accompanied by a rapid and transient increase in the number of gamma/delta T cells present within the intestinal villi. In response to a challenge infection in immune calves, there is a substantial increase in the number of CD4+ T cells present in the Peyer's patch of the ileum and a specific localization of CD8+ T cells to the epithelium of the intestinal villi. Together, these data demonstrate that C, parvum elicits a strong cell-mediated response following both primary and secondary infections in calves, and that CD8+ T cells may play an important role in the bovine immune response to C. parvum infection.     

Differential responses to chemoimmunotherapy in patients with metastatic malignant melanoma

An open, multicentre non-randomised study was performed to evaluate the activity and toxicity of combination chemoimmunotherapy, consisting of cisplatin, interleukin-2 and interferon-alpha, in metastatic malignant melanoma. Between March 1992 and September 1993, 28 patients with pathologically proven metastatic malignant melanoma, bidimensionally measurable disease and an Eastern Co-operative Oncology Group score < or = 1 were treated with the combination chemoimmunotherapy. The regimen consisted of cisplatin (100 mg/m2 on day 0), interleukin-2 (Proleukin, Chiron, Middlesex, U.K.) 18 x 10(6)IU/m2/d continuous intravenous infusion on days 3-7 and 17-22, with interferon-alpha (Roferon-A, Roche, Hertfordshire, U.K.) 9 x 10(6) U/d subcutaneously on days 3, 5, 7, 17, 19, 21 during the interleukin-2 infusions. The treatment cycle lasted 28 days. Among 27 assessable patients, 5 patients achieved partial responses, for an overall response rate of 18% (95% CI 6-37%). Median progression-free survival was 44 days (range 8-279) and median overall survival was 264 days (range 41-1432). Differential responses were noted in 41% of patients and responses were more frequent in non-visceral disease (skin, lymph node and soft tissue disease) (P = 0.04). These results indicate that differential responses to chemoimmunotherapy are common in patients with metastatic melanoma. This may account for the broad range of response rates reported in the literature.     

T cell responses and viral escape

OBJECTIVE: Median sternotomy was performed by 2 different techniques in order to determine whether there was a difference in the incidence of inadvertent pleural entry. EXPERIMENTAL DESIGN: Patients were prospectively evaluated and reviewed at a mean follow-up interval of 8.2 months. PATIENTS AND METHODS: Ninety five consecutive patients underwent primary sternotomy at a single tertiary referral center. MEASURES: Planned outcome measures included, incidence of pleural entry, length of hospitalization, and chest tube site related postoperative morbidity. RESULTS: Group 1 (n=49) had sternotomy undertaken from the sternal notch proceeding downwards. Group 2 (n=46) underwent sternotomy performed from the xiphoid upwards. Mediastinal evaluation revealed a significant reduction in the incidence of pleural violation for group 1 (3) versus group 2 (11) (p=0.014). This difference was not found to be surgeon specific. CONCLUSIONS: Sternotomy undertaken from the sternal notch proceeding downwards is shown to be associated with a reduced incidence of inadvertent pleural entry. Potential advantages for this approach also include reduced respiratory morbidity, less chest tube site complications and a trend to reduced length of hospitalization.     

Chemokine production by a human alveolar epithelial cell line in response to Mycobacterium tuberculosis

To investigate the role of chemokines during the initial local response to Mycobacterium tuberculosis in the human lung, we studied chemokine production by the human alveolar epithelial cell line A549 after infection with M. tuberculosis. M. tuberculosis-infected A549 cells produced mRNAs and protein for monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) but not mRNAs for macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES. Chemokine production in response to M. tuberculosis was not dependent on production of tumor necrosis factor alpha, IL-1beta, or IL-6. Two virulent clinical M. tuberculosis isolates, the virulent laboratory strain H37Rv, and the avirulent strain H37Ra elicited production of comparable concentrations of MCP-1 and IL-8, whereas killed M. tuberculosis and three Mycobacterium avium strains did not. The three virulent M. tuberculosis strains grew more rapidly than the avirulent M. tuberculosis strain in the alveolar epithelial cell line, and the three M. avium strains did not grow intracellularly. These findings suggest that intracellular growth is necessary for mycobacteria to elicit production of MCP-1 and IL-8 by alveolar epithelial cells but that virulence and the rate of intracellular growth do not correlate with chemokine production. Alveolar epithelial cells may contribute to the local inflammatory response in human tuberculosis by producing chemokines which attract monocytes, lymphocytes, and polymorphonuclear cells.     

Differential activation of T cells by natural antigen peptide analogues: influence on autoimmune and alloimmune in vivo T cell responses

Recent studies using synthetic altered peptide ligands (Analogues) have led to the fine dissection of TCR-mediated T cell functions elicited by Ag recognition. Certain Analogues behave as full agonists of the antigenic peptide while others are partial agonists in that they only trigger selected T cell functions. Additionally, peptide Analogues can behave as antagonists by inhibiting functions of T cell clones when coincubated with the wild-type peptide. In fetal thymic organ cultures, synthetic altered peptide ligands can impact T cell repertoire selection. However, the influence of naturally occurring peptide Analogues on T cell immunity in vivo remains hypothetical. We previously reported that, in B10.A mice, immunogenicity and tolerogenicity of the self-MHC class I peptide, Ld 61-80, were influenced by the presentation of a cross-reactive self-peptide, Kk 61-80. Here, we show that Kk 61-80 self-peptide represents a partial agonist of Ld 61-80 in that it induced the proliferation but not the lymphokine production of Ld 61-80-primed T cells. Next, we showed that presentation of Kk 61-80 Analogue peptide mediated T cell tolerance toward Ld 61-80 self-peptide. Alternatively, when Ld protein represented an alloantigen displayed on transplanted cells, immunization with Kk 61-80 Analogue sensitized recipient mice to Ld 61-80 peptide, thus inducing potent immune responses to donor cells. These results show that the presentation of natural Analogue peptides may represent an essential component of T cell responses involved in autoimmunity and transplant rejection.