Quantification of total sheep IgE concentration using anti-ovine IgE monoclonal antibodies in an enzyme immunoassay

Monoclonal antibodies (mAbs) which recognize separate epitopes on ovine immunoglobulin E (IgE) have been used to develop a non-competitive antibody sandwich enzyme immunoassay (EIA) for quantitating ovine IgE. Purified anti-IgE mAb (YD3) coated onto polystyrene microtitre plates was used to capture IgE in serum samples. Biotinylated anti-IgE mAb (XB6) followed by streptavidin conjugated with horseradish peroxidase were used to detect captured IgE. Tetramethylbenzidine and H2O2 were used as enzyme substrate. A reference serum was prepared by pooling sheep sera containing elevated IgE levels. This reference serum was assigned a value of 100 units ml-1 and used to prepare standard curves for the EIA. The linear region of log-log transformed standard curve data covered a range of 0.05-0.8 units ml-1. The equation of a linear regression line fitted to this curve was used to determine sample concentrations. Using purified IgE, 1 unit of reference serum was equivalent to 0.86 micrograms ml-1 IgE. Maximum intra- and inter-assay coefficients of variation for the EIA were 4.6% and 9.7%, respectively. Subjecting serum samples to 15 freeze/thaw cycles, storage at room temperature for 16 days or incubation at 37 degrees C for 8 h resulted in minimal loss of IgE detection. Incubation of serum at 56 degrees C resulted in rapid reduction in detection of IgE by the EIA. The assay was used to determine IgE levels in adult sheep monospecifically infected with weekly doses of the nematode Trichostrongylus axei. Serum IgE levels increased from 9 to 16 days following first infection and reached maximum levels by days 35-58. Serum IgE responses closely followed IgE positive cell responses in the abomasal mucosa.

Production of tumor necrosis factor and nitric oxide by macrophages infected with live and dead mycobacteria and their suppression by an interleukin-10-secreting recombinant

We have analyzed mycobacterium-induced cytokine secretion in the J774A.1 macrophage-like cell line. Tumor necrosis factor alpha (TNF-alpha) was preferentially induced by live organisms, both slow and rapid growing. Expression of interleukin-10 by a recombinant strain of Mycobacterium smegmatis caused reduced production of TNF-alpha and nitric oxide during the early stages of infection.

Rapid detection of multidrug-resistant tuberculosis

Transmission of multidrug-resistant strains of Mycobacterium tuberculosis (MDR-TB) presents a serious problem for infection control in hospitals, particularly in the context of co-infection with the human immunodeficiency virus (HIV). We report on the use of molecular genetic tools to allow rapid assessment of samples from patients potentially infected with MDR-TB. Sputum and bronchoalveolar lavage samples were obtained from two HIV-positive patients with suspected tuberculosis, who had previous contact with a known MDR-TB index case. Polymerase chain reaction (PCR) was used directly on clinical samples to amplify genetic loci associated with rifampicin resistance (rpoB), and strain-specific polymorphisms (the direct repeat (DR) region). Drug resistance was determined using a commercially available kit for detection of point mutations in the rpoB gene (Inno-Lipa RifTB; Innogenetics, Belgium), and confirmed by nucleotide sequencing. Strain variation was determined using the spoligotyping method, based on the presence or absence of variable linker sequences within the DR region. In one patient, infection with a MDR strain identical to that of a known index case was demonstrated. A second patient, although positive for M. tuberculosis, was found to be infected with a rifampicin-sensitive strain. Results were obtained within 48 h, allowing appropriate treatment to be initiated and infection control measures to be implemented. PCR-based tests for strain-typing and for identification of rifampicin resistance provide important tools for identifying patients with MDR-TB and for rapid monitoring of potential nosocomial spread of MDR-TB. Prompt confirmation or exclusion of possible transmission allows early clinical intervention to prevent future outbreaks of multidrug-resistant M. tuberculosis.

Temperament in juvenile eating disorders

Previous studies have suggested an association between temperament and eating disorder pathology. The purpose of this study was to differentiate on the basis of temperament among patients with anorexia, bulimia, and major depression. In this study, 101 adolescent girls completed the Revised Dimensions of Temperament Survey (Self), a self-report measure that identifies nine dimensions of temperament. Significant differences were found between the diagnostic groups while controlling for disturbances in mood and defensiveness. Specific subscales differentiated the subjects with anorexia from those with bulimia. These data support the concept of using temperament to differentiate patients with related psychiatric syndromes.

Differentiation of Mycobacterium tuberculosis isolates by spoligotyping and IS6110 restriction fragment length polymorphism

Mycobacterium tuberculosis isolates from 167 patients attending three London hospitals were analyzed by two techniques for strain differentiation. A significant number of isolates that appeared identical with the recently developed spoligotyping system could be distinguished from each other by IS6110 restriction fragment length polymorphism analysis, with the latter technique demonstrating a generally higher level of discrimination. Spoligotyping, on the other hand, was particularly useful for analysis of isolates with low IS6110 copy numbers, and use of the two techniques in tandem provided an optimal approach to the identification of clusters with epidemiological evidence consistent with recent transmission. Spoligotyping can be applied directly to clinical samples by PCR and provides an important tool for the rapid detection of nosocomial transmission of individual strains.

Pulmonary artery occlusion by tuberculous mediastinal lymphadenopathy

Two cases of tuberculous mediastinal lymphadenopathy are presented in which the clinical features mimicked those of pulmonary embolism, causing striking abnormalities on radionuclide scintigraphy. It is concluded that tuberculous mediastinal lymphadenopathy should be included in the differential diagnosis of reduced lung perfusion due to proximal pulmonary artery occlusion.

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.

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.

Interleukin-10- and corticosteroid-induced reduction in type I procollagen in a human ex vivo scar culture

Fibroblasts act as the effector cells of the fibrotic response via production of collagen. In an attempt to understand the regulation of fibroblasts from areas of active human tissue fibrosis, we have developed an ex vivo model in which biopsies of scars from patients 6 weeks post thoracotomy were cultured. This model has been used to investigate whether interleukin-10 (IL-10) and triamcinolone acetonide modulate the expression of type I procollagen mRNA and protein. In situ hybridization and a quantitative competitive RT-PCR were used to measure type I procollagen mRNA. Type I procollagen protein was evaluated by immunochemistry. Viability of biopsies in culture using 3H-uridine incorporation into RNA was observed to be > 80% for at least 96 hours. Following addition of either IL-10 or triamcinolone acetonide there was a modest but significant decrease (P < 0.05) in type I procollagen mRNA expression. Similarly, each agent added individually to biopsies reduced the proportion of cells staining positively for type I procollagen when compared to biopsies treated with medium alone (P < 0.05). These results extend in vitro data that IL-10 and corticosteroids down-regulate collagen synthesis in skin fibroblast cell lines and suggest that this ex vivo model may offer a closer approximation to the post-operative scarring process when testing new therapeutic agents for reducing an over-exuberent fibrotic response.

Thalidomide reduces tumour necrosis factor-alpha production by human alveolar macrophages

Overexuberant production of tumour necrosis factor-alpha (TNF-alpha) by macrophages and other cells is thought to contribute to the development of permanent lung damage in many inflammatory conditions. There is a need for an agent, without the side-effects of corticosteroids, which can reduce the production of TNF-alpha by macrophages activated by disease. This study evaluated the effect of thalidomide on lipopolysaccharide (LPS)-induced TNF-alpha production by human alveolar macrophages obtained from patients with tuberculosis and a group of other diseases associated with macrophage activation. Alveolar macrophages obtained by bronchoalveolar lavage from 31 patients (tuberculosis = 12, sarcoidosis = 3, lung cancer = 5, chronic bronchitis = 5, pneumonia = 6) were stimulated with LPS alone or LPS in combination with either thalidomide or dexamethasone. Cell-associated TNF-alpha, as measured by immunochemistry, and TNF-alpha released by macrophages, as assessed by ELISA, were markedly increased when cells were incubated with LPS (P < 0.05), and both were decreased following addition of thalidomide (P < 0.05) or dexamethasone (P < 0.05) to amounts similar to those observed when macrophages were incubated with medium alone. Similarly, TNF-alpha mRNA as measured by in situ hybridization was increased following incubation with LPS (P < 0.05), but this increase was prevented by addition of thalidomide (P < 0.05) or dexamethasone (P < 0.05). The ability of thalidomide to reduce LPS-induced TNF-alpha production by alveolar macrophages was the same when cells from patients with tuberculosis (a disease associated with TNF-alpha production) and cells from patients with the other conditions were compared. The ability of thalidomide to reduce TNF-alpha production by human alveolar macrophages from patients with active lung disease suggests that thalidomide and its analogues may have potential as drugs to reduce TNF-alpha production in disease.

Increased inflammatory cytokines and new collagen formation in cutaneous tuberculosis and sarcoidosis

BACKGROUND

Interactions between mononuclear cells, vascular endothelium, fibroblasts, and cytokines during the inflammatory reaction within a granuloma have the potential to contribute to the progression to fibrosis.

METHODS

Biopsy specimens of six tuberculous and eight sarcoidosis skin lesions were examined by immunohistochemistry to seek evidence for the presence of inflammatory and fibrotic reactions in human granulomatous disease. Additionally, to understand how a T cell mediated delayed type hypersensitivity reaction--a component of chronic granulomatous inflammation--could progress to fibrosis, the human in vivo model of the cutaneous tuberculin Heaf reaction to purified protein derivative (PPD) was studied in a group of 48 subjects.

RESULTS

Granulomas from tuberculous and sarcoidosis skin biopsy specimens were seen to contain cells with marked staining by antibodies to fibronectin, transforming growth factor beta (pan TGF-beta), and type 1 procollagen (PCP-1). Accentuated staining of extracellular matrix was seen both in the granulomas and in the peri-granulomatous regions. Less prominent staining was observed using antibodies against interleukin 1 beta (IL-1 beta) and alpha-smooth muscle actin (alpha-SMA). Biopsies of Heaf reactions revealed cells staining for IL-1 beta, tumour necrosis factor alpha (TNF-alpha), platelet derived growth factor B (PDGF-B), and fibronectin which were detected as early as day 1 and persisted throughout the 14 day study period. Cells staining for PCP-1 increased to greatest abundance at day 14. All these cytokines were present in low abundance in biopsy specimens from sites inoculated with saline only.

CONCLUSIONS

Evidence is provided that granulomas in tuberculosis and sarcoidosis behave as active centres of fibrogenesis. Using the Heaf model, the temporal relationship between the early appearance of cytokines and the later increase in the collagen precursor PCP-1 linked the immune mediated chronic inflammatory response with subsequent fibrosis and suggested that the tuberculin Heaf reaction will serve as a model for studying the early events of granuloma formation in patients with tuberculosis and sarcoidosis.

Increase in interleukin (IL)-1 beta and IL-6 in bronchoalveolar lavage fluid obtained from infants with chronic lung disease of prematurity

Chronic lung disease (CLD) of prematurity is associated with an initial increase in pulmonary neutrophils followed by pulmonary fibrosis. We determined whether the proinflammatory cytokines, IL-1 beta and IL-6, were increased in the bronchoalveolar lavage fluid obtained from nine infants (median gestation 25 wk, birthweight 820 g) who developed CLD, seven (28 wk, 1110 g) who recovered from the respiratory distress syndrome (RDS), and four (38 wk, 2690 g) control infants. IL-1 beta and IL-6 protein were both increased in the bronchoalveolar lavage fluid from the CLD groups when compared with the RDS and control groups. This difference for both the cytokines was most marked on d 10 of age, when results from infants with and without CLD were compared (IL-1 beta, 4.6 versus 1.1 ng/mL, p < 0.05; and IL-6, 9.5 versus 1.5 ng/mL, p < 0.05). Immunocytochemistry of lavage cells for IL-1 beta, IL-6, and IL-8 protein showed alveolar macrophages to contain all three cytokines, with lesser staining evident in neutrophils, and in epithelial cells occasionally obtained by lavage. The contribution of alveolar macrophages and luminal cells to the increase in IL-6 and IL-1 was determined by performing semiquantitative reverse transcription-polymerase chain reactions on RNA extracted from lavage cells. IL-6 mRNA expression was increased in lavage cells from the CLD infants when compared with the RDS group. However, the expression for IL-1 beta and IL-8 mRNA was similar in both groups. These results suggest that IL-1 beta, IL-6, and IL-8 may contribute to the pathogenesis of CLD, and that, in CLD, IL-6 may be produced by cells within the air spaces.

Sequential cellular and humoral responses in the abomasal mucosa and blood of Romney sheep dosed with Trichostrongylus axei

Abomasal cannulae were surgically placed in 7 2-year-old New Zealand Romney sheep which had been maintained parasite-free from birth. Four of these sheep were randomly selected and dosed orally with 10,000 infective Trichostrongylus axei larvae per week for 8 weeks, while the remaining 3 sheep served as uninfected controls. Abomasal biopsy, blood and faecal samples were obtained from all sheep at regular intervals from 5 days before and until 58 days after the first infection. The sheep were then killed, worm burdens assessed and abomasal and small intestinal samples collected Faecal egg counts of all 4 dosed sheep were low and only one (No. 701) had a substantial worm burden (8400) post mortem. Overall, levels of mucosal mast cells/globule leukocytes, eosinophils, T19+ cells and larval migration inhibitory activity increased significantly in the abomasal mucosa of the dosed sheep compared to the controls. The CD4+:CD8+ cell ratio in the abomasal mucosa of the dosed sheep also increased compared to that of the controls (P = 0.06). In blood, T. axei-specific antibody (total and IgG1) and eosinophil numbers increased significantly in the dosed sheep. Mucosal cells staining for IgE (IgE+), and blood and mucosal eosinophils showed the earliest substantive increases in number followed by increases in specific serum antibody levels, numbers of mucosal cells fluorescing under UV light (UVf) and T19+ cells. The difference in the IgE+ and UVf cell responses indicated that expansion of globule leukocyte numbers lagged behind that of mucosal mast cells. The results supported the concept of CD4+ T cell help in the abomasal mucosa and defined the sequential expression of components of the immunological responses potentially mediating resistance to T. axei. In sheep No. 701, persistence of adult worms was associated with lower mucosal IgE+ cell and eosinophil responses compared with the other dosed sheep.

A prospective clinical evaluation of the longevity of resorbable sutures in oral mucosa

A prospective, randomised and controlled clinical investigation was undertaken to evaluate the longevity of resorbable sutures in the oral environment. The sutures investigated were gut, polyglycolic acid and polyglactin 910, were of standard gauge and needle type, and were placed using a standard technique by trained clinicians. The sutures were monitored following apical surgery in 55 patients (110 sutures) and the median survival values were: gut - 4 days, polyglycolic acid - 15 days, polyglactin 910 - 28 days. These differences were highly statistically significant. A postal survey of 30 randomly selected oral and maxillofacial surgeons reveal most prefer to use resorbable sutures, with softgut the most popular choice. Most would like an ideal resorbable suture to last 5 to 14 days and in this respect none of the materials tested appears satisfactory.

Production and characterisation of monoclonal antibodies recognising ovine IgE

Two monoclonal antibodies (mAbs), XB6 and YD3, which recognise ovine immunoglobulin E (IgE) were produced. Mast cells isolated from ovine intestinal mucosa were used as a source of IgE to immunize mice. Culture supernatants of hybridomas were screened by immunoassays on small-intestine tissue sections, isolated mucosal cells, and dot blots of lysed mast cell homogenate. Two mAbs were chosen for their specific binding to mast cells. Antigen bound by these mAbs was purified by immunoaffinity chromatography using XB6 mAb, and this produced two bands consistent with IgE heavy chain (86,000 Daltons) and immunoglobulin light chain (28,000 Daltons) when run under reducing conditions on SDS-PAGE gels. Purified IgE was shown on dot blots to react weakly with mAb to chimeric ovine IgE and strongly to polyclonal anti-sheep antibodies. The two mAbs induced an immediate hypersensitivity-like reaction when injected into the skin of sheep. The mAbs bound to mast cells and other mononuclear cells, presumably IgE-secreting B-cells in mesenteric lymph node sections. These mAbs proved useful for detecting IgE-bearing cells in various ovine tissues, for purifying mast cells from cell isolates by panning and immunomagnetic bead separation, for purifying serum IgE using immunoaffinity chromatography and for detecting IgE in an ELISA. Competitive binding assays showed that the two mAbs bind to different epitopes on IgE. These mAbs will be useful in research applications and in diagnostic assays.

The immune response of sheep surgically modified with intestinal loops to challenge with Trichostrongylus colubriformis

Aspects of the local immune response to nematode challenge were investigated in vivo in isolated loops of the upper small intestine of mature sheep that were immunised by repeated infections with Trichostrongylus colubriformis infective larvae (L3). Groups of 3 sheep were challenged either through the loop (Group 1) or orally (Group 2) with T. colubriformis L3, the third group served as unchallenged controls (Group 3). Nematode specific antibody levels, mast cell proteinase levels (SMCP) and larval migration inhibition (LMI) activity were determined in loop secretions for 4 weeks after challenge. The intestinal loops remained functional throughout the experiment. Groups 1 and 2 were re-challenged 2 weeks after the first challenge, and all 3 Groups were slaughtered 2 weeks later. Histopathological examination showed elevated numbers of globule leukocytes (GL) in both the nematode-challenged loop and unchallenged small intestine of Group 1 and small intestine of Group 2 indicating that nematode infections induce the local appearance of large numbers of GL. Oral, but not loop challenge caused increased antibody levels in loop secretions when compared to unchallenged controls. Only loop-challenged sheep showed a peak in loop fluid SMCP levels 10-13 days after the first challenge which coincided with a peak in numbers of mucosal GL. The isolated loops of all 3 groups showed highly elevated numbers of eosinophils when compared to the intact small intestine. Loop fluid of all 3 groups showed a high level of LMI activity reflecting the high level of nematode-resistance induced by the immunisation procedures. Sheep in Groups 1 and 2 were both able to expel challenge infections, and when compared to Group 3, showed higher blastogenic activity of unstimulated cells derived from a mesenteric lymph node in the region of the challenged part of the intestine. The present experiment showed that surgically constructed intestinal loops provided a model system by which the substantial changes associated with the local intestinal immune response to challenge with T. colubriformis could be investigated.

Increase in the concentration of transforming growth factor beta-1 in bronchoalveolar lavage fluid before development of chronic lung disease of prematurity

OBJECTIVE

Pulmonary fibrosis is a prominent feature of chronic lung disease of prematurity (CLD). We sought to determine the influence of the potent profibrotic cytokine transforming growth factor beta-1 (TGF-Beta 1) on the development of CLD.

METHODS

We determined the concentration of active and total TGF-Beta 1 in bronchoalveolar lavage fluid obtained from 18 infants who subsequently had CLD (mean gestation, 25.7 weeks; birth weight, 816 gm) 15 (29.8 weeks, 1493 gm) who recovered from the respiratory distress syndrome, and 7 (35.1 weeks, 2441 gm) control infants.

RESULTS

The concentration of both active and total TGF-Beta 1 was increased in the infants with CLD when compared with the respiratory distress syndrome and control groups. The increase in active and total TGF-Beta 1 was greatest on day 4 of age, when infants who eventually had CLD were compared with those who did not progress to CLD (active TGF-Beta 1, 39.5 vs 4.6 ng/ml; total TGF-Beta 1, 43.8 vs 13.8 ng/ml). In addition, immunocytochemistry studies localized pan-TGF-Beta to alveolar macrophages obtained by bronchoalveolar lavage.

CONCLUSIONS

These observations indicate that TGF-Beta 1 may contribute to the fibrotic response that is observed in the lungs of infants who have CLD.

Cross-reacting antibodies to Sarcoptes suis, Chorioptes bovis and Notoedres cati and anti-P. ovis IgE in sera from sheep infested naturally with Psoroptes ovis

For the development of immunodiagnostic tests to detect mange mite infections in man and animals, it is necessary to know about antigen structure and cross-reactivity between different mite species and other arthropods in contact with the host. Sera from sheep infected with Psoroptes ovis (sheep anti-P. ovis sera) showed positive reactions in dot blots to P. ovis antigen and cross-reactivity to crude antigen extracts from Sarcoptes suis, Notoedres cati and Chorioptes bovis. Using sheep Specific Pathogen Free (SPF) sera in dot blots, weak reactions were seen to all but the Ch. bovis antigen. In SDS PAGE-separated P. ovis antigens at least 35 different proteins could be distinguished. In western blots, at least 24 out of these 35 were recognized as antigens by sheep anti-P. ovis immunoglobulins. At least 13 were recognized by sheep anti-P. ovis IgE. One of these, at 19 kDa, was recognized only with sheep anti-P. ovis IgE, the other 12 also with anti-P. ovis immunoglobulins. Cross-reactive antigens were recognized by sheep anti-P. ovis immunoglobulins in SDS PAGE-separated, and nitrocellulose transferred mite extracts in western blots as follows: 13 antigens in S. suis extracts, 9 in N. cati and 8 in Ch. bovis. Sheep SPF sera recognized an antigen at 67 kDa in each of these 4 mite species. Rabbit anti-sheep immunoglobulins in the P. ovis antigen control bound to a protein at 28 kDa which may be sheep IgG light chain taken up by P. ovis feeding on sheep. Despite the antigenic similarities between mange mites, sufficient differences were apparent to make immunodiagnostic tests for mange feasible.

Thunderstorm associated asthma: a detailed analysis of environmental factors

OBJECTIVES

To seek associations between meteorological factors, concentrations of air pollutants or pollen, and an asthma epidemic which occurred in London on 24 and 25 June 1994 after a thunderstorm.

DESIGN

Retrospective study of patients' accident and emergency department records, with bivariate and multivariate analysis of environmental factors and data collection for the two months surrounding the epidemic.

SETTING

The accident and emergency department of St Mary's Hospital in west central London.

SUBJECTS

148 patients presenting with asthma between 1 June and 31 July 1994, of whom 40 presented in the 24 hours after the storm.

RESULTS

The asthma epidemic was significantly associated with a drop in air temperature six hours previously and a high grass pollen concentration nine hours previously. Non-epidemic asthma was significantly associated with lightning strikes, increase in humidity or sulphur dioxide concentration, a drop in temperature or high rainfall the previous day, and a decrease in maximum air pressure or changes in grass pollen counts over the previous two days.

CONCLUSIONS

New episodes of asthma during the epidemic on 24 and 25 June 1994 were associated with a fall in air temperature and a rise in grass pollen concentration. Non-epidemic asthma was significantly associated with a greater number of environmental changes. This may indicate that the patients with thunderstorm associated asthma were a separate population, sensitive to different environmental stimuli.