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Biomedical subjects

S Ahlstedt

Publications and source records attributed to S Ahlstedt.

At least 19 recordsLinked to original sources
PubMed1992

Induction of IgE antibodies and T-cell reactivity to ovalbumin in rats colonized with Escherichia coli genetically manipulated to produce ovalbumin.

The immune response to ovalbumin (OA) and the bacterial antigens, lipopolysaccharide (LPS) and fimbriae were studied in conventional rats colonized from birth with an Escherichia coli strain producing OA. The colonized rats had developed IgE antibodies against OA, but not against the fimbrial or the LPS antigens from the E. coli at 2 months of age. At this time all rats were primed with OA given intracutaneously in Freund's complete adjuvant. Two weeks later the colonized rats showed a 35% greater delayed-type hypersensitivity (DTH) reaction to OA, measured as ear swelling, than the controls. Thus bacteria carrying antigens resembling potential allergens might aggravate, or participate in the induction of allergic symptoms. In addition such bacteria could be efficient vaccine vectors in protection against parasites. The study illustrates the importance of the mode of antigen presentation for the subsequent immune response.

Animals↗
PubMed1991

Indirect evidence of bronchial inflammation assessed by titration of inflammatory mediators in BAL fluid of patients with asthma.

Bronchial inflammation is a characteristic of asthma that may be examined indirectly by bronchoalveolar lavage (BAL). Nine normal individuals were compared with 38 age-matched adults with asthma of variable severity to appreciate the importance of cell activation in the severity of asthma. The severity of asthma was appreciated by the clinical score of Aas and the pulmonary function of the patients. FEV1 ranged between 35% and 130% of predicted. The indirect activation of eosinophils (EOSs), mast cells, fibroblasts, and neutrophils was examined by the titration of eosinophil cationic protein (ECP), tryptase, hyaluronan (HA), and myeloperoxidase (MPO) by radioimmunoassay in BAL fluid (BALF) and cytology of BALF. In the adults with asthma, there was a significantly increased number of EOSs and a significantly increased level of all mediators but MPO. MPO levels were increased in seven patients only; three of these patients were previous smokers. Only ECP and HA levels were significantly correlated with the severity of asthma. These results demonstrate EOSs, mast cells, and fibroblasts are activated in asthma, whereas the involvement of neutrophils is less clear. There was a significant correlation between ECP and HA levels, suggesting a common activation of EOSs and fibroblasts.

Adult↗
PubMed1991

Antibody-dependent cell-mediated cytotoxicity to beta-lactoglobulin-coated cells with sera from children with intolerance of cow's milk protein.

The capacity of serum antibodies against beta-lactoglobulin to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) was analysed in sera from children with cow's milk protein intolerance (CMPI). The children with CMPI were divided into three groups according to clinical features: delayed-onset CMPI with gastrointestinal symptoms (n = 8); immediate-onset CMPI with gastrointestinal and skin symptoms (n = 8); and immediate-onset CMPI with skin symptoms only (n = 8). The CMPI groups were compared with children with untreated (n = 9) or treated (n = 8) coeliac disease and a control group (n = 22). Sera from the children were examined for cytotoxic effects using lymphocytes from healthy adults as effector cells and radiolabelled beta-lactoglobulin-coated erythrocytes from the same donor as target cells. In addition, IgG and IgA serum antibodies against beta-lactoglobulin were determined with ELISA. Sera from children with CMPI and gastrointestinal symptomatology showed a significantly increased capacity to induce ADCC reactivity as compared with controls. This increased capacity was seen in sera from those with immediate as well as delayed onset of the gastrointestinal symptoms. In contrast, sera from children who had an immediate-onset CMPI with only skin symptoms mediated no such increase in ADCC reactivity. Moreover, children with coeliac disease with a few exceptions, demonstrated low ADCC reactivity, despite the fact that they had high levels of antibodies against beta-lactoglobulin. ADCC may be an immunopathogenic mechanism in certain cases of CMPI with gastrointestinal symptoms.

Antibodies↗
PubMed1991

Enhancement of IgE synthesis in the human myeloma cell line U-266 with an IgE binding factor from a human T-cell line.

An IgE-binding factor(s) (IgE-BF(s] was partially purified from the supernatant of human HTLV-II carrying T-cell line MO. This IgE-BF(s) was shown to increase the IgE synthesis in the human myeloma cell line U-266, but did not affect its viability or growth. The effect of the IgE-BF(s) was dose-dependent and selective for IgE protein synthesis as beta 2-microglobulin synthesis in the U-266 and the immunoglobulin production in the U-1958 IgG-secreting human myeloma cell line were unaffected. The IgE-BF(s) increased the production of the epsilon heavy chain but not the lambda light chain production. The IgE-BF(s) was distinct from IL-1 beta, IL-3, IL-4, IL-5, IL-6, TNF-alpha, IFN-alpha, -beta, -gamma, M-CSF, and fragments of CD23.

Cytokines↗
PubMed1991

Local immune response and bronchial reactivity in rats after capsaicin treatment.

The interaction between the nervous system, immune system and bronchial reactivity was studied in rats by using the neurotoxin capsaicin. Rats were treated with capsaicin at 1-2 days of age or at adult age, before or after sensitization by subcutaneous injections with ovalbumin (OA). The levels of the neuropeptides neurokinin A and calcitonin gene-related peptide were decreased in the lung after capsaicin treatment, as determined with radioimmunoassay, whereas the levels of neuropeptide Y were unaffected. The levels of IgA, IgE and IgG in bronchial lavage were also affected by capsaicin treatment; however, the results were heterogeneous. Capsaicin treatment after sensitization reduced the bronchial reactivity to challenge with OA aerosol and serotonin iv. The results demonstrated that reduction of neuropeptide levels with capsaicin affected both bronchial reactivity and the levels of antibodies in bronchial lavage fluid. However, no correlation between these two parameters was seen, demonstrating the complexity of the system.

Animals↗
PubMed1991

IgE-positive duodenal mast cells in patients with food-related diarrhea.

Thirty-seven consecutive adult patients with a history of adverse reactions to foods, manifested mainly as diarrhea, were investigated with skin prick test (SPT), IgE levels in serum, and the presence of IgE bound to mast cells in duodenal biopsy specimens. Nineteen percent had increased serum IgE levels indicating the presence of atopic disease and in 35% positive SPTs for one or several allergens related to their gastrointestinal symptoms were found. In 92% of the patients with positive SPTs to food, IgE-positive mast cells in duodenal biopsy specimens were found, twice as many as in patients with negative SPTs (47%). Forty-two percent of normal individuals without any adverse reactions to foods had IgE-bearing mast cells in their intestinal mucosa. The results showed that 'arming' of mast cells with IgE locally was relatively prominent but not consistent in the gut of patients with food-related diarrhea suggested to be allergic by positive SPT. Intestinal IgE-mediated hypersensitivity reactions could be of pathogenetic significance in most of these patients. However, since also half of the normal individuals were found to have IgE-positive intestinal mast cells, this phenomenon presumably also reflects a normal physiological defence mechanism.

Adult↗
PubMed1991

Cultures of human cord blood metachromatic cells in relation to family history of atopy, development of atopic disease, nasal metachromatic cells and perinatal factors.

The appearance of basophilic cells by maturation from progenitors was studied in cultures of cord blood mononuclear cells (CB-MNC) from 83 newborns. In unstimulated cultures, the numbers of basophilic cells increased 5-fold after 14 days of cultivation. This increase and the cell numbers were similar in cultures from atopic individuals and controls. Other cultures were stimulated with conditioned medium (CM) prepared from 3-day cultures of blood cells from atopic individuals activated with allergen or with CM from the Mo leukemic cell line. The addition of such CM resulted in an increase in the number of basophilic cells, as compared to the cultures which were unstimulated (p less than 0.01). No correlation was found between the maturation of basophils and heredity for atopy, development of atopic disease, appearance of metachromatic cells in the nasal mucosa and perinatal factors, such as maternal infections, perinatal stress, birth weight, month of birth and IgE levels. The study confirmed that basophilic cells can be driven to mature in cultures of CB-MNC, although the maturation did not seem to depend on atopic predisposition as indicated by family history of allergy and CB IgE levels nor on symptoms and signs of atopic disease during the first 18 months of life. Therefore, the predictive value of elevated basophilic cell numbers in CB or CB-MNC cultures with regard to allergic disease seemed to be limited.

Basophils↗
PubMed1990

A fluorescence method for the visualization of inflammatory cells in intestinal mucosa.

Treatment of paraffin or cryostat sections from rat, rabbit and man, with fluorescein isothiocyanate (FITC) in buffer (1 microgram/l), resulted in visualization of highly fluorescent leukocytes with a granular staining in light microscopy. FITC staining of paraffin-embedded colonic tissue was compared with three other staining methods, i.e., (1) FITC-conjugated anti-neutrophil antibodies, (2) endogenous peroxidase with 3,3-diaminobenzidine, and (3) FITC-conjugated Lotus tetragonolobus lectin. Good correlations between FITC staining and the three other methods were found (r:0.97, 0.98 and 0.98; P less than 0.001). Inhibition of receptors for the FITC conjugates prior staining, by preincubation with unconjugated anti-neutrophil antibodies or L-fucose, abolished the staining with antibodies and lectin. This study shows that staining with unlabeled FITC represents a quick and convenient method for the estimation of phagocytic cells (polymorphonuclear cells and macrophages) in histological specimens.

Animals↗
PubMed1990

Immune complex induced experimental colitis: beneficial effect of sulphasalazine in rabbits.

Experimental colitis was induced in rabbits by exposing the colon mucosa to 1% formalin followed by i.v. injections of soluble immune complexes made with antigen in excess. The animals were preimmunized with Escherichia coli O14:K7:H--inducing antibodies cross-reactive to intestinal epithelium. Animals with this colitis were divided in two groups. One group was treated with sulphasalazine and the other was given vehicle only. Sulphasalazine was administered daily at 125.5 mumol (50 mg) per kg body weight. The administration was started at the same day as the colitis was initiated. At Day 6, 13 and 30 following induction of colitis, biopsies were sampled and histologically evaluated. Inflammation was assessed by scores for inflammatory cells, crypt distortion, decreased crypt number and presence of crypt abscesses, thus corresponding to the picture seen in humans. A statistically significant lower score of inflammation was seen on Day 6 and 13 (P less than 0.01) and on Day 30 (P less than 0.05) following induction of colitis in animals treated with sulphasalazine.

Animals↗
PubMed1990

Characteristics of immune-complex-induced chronic experimental colitis in rats with a therapeutic effect of sulphasalazine.

Experimental colitis was induced in rats by topical irritation of the colonic mucosa with 1 ml of 1% formalin followed by intravenous injection of 0.5 ml soluble immune complexes (IC) made in vitro in antigen excess and having characterized precipitation and complement activation profiles. The rats had been preimmunized with Escherichia coli O14:K7:H- to produce antibodies cross-reactive with colonic mucosa, thus aggravating the colitis to chronicity. Histologic evaluation of inflammation in the colon was performed on days 6, 12, and 18 by determining the number of phagocytic cells. The colitis was inhibited by sulphasalazine therapy given daily, 125.5 mumols (50 mg)/kg body weight, starting on the day when the inflammation was produced with IC and formalin. Sulphasalazine therapy significantly (p less than 0.05) decreased the number of phagocytic cells in the mucosa on days 12 and 18 but not on day 6. The results may give a clue to the beneficial pharmacologic effects of sulphasalazine in the treatment of ulcerative colitis.

Animals↗
PubMed1979

Effects of subinhibitory amounts of ampicillin, amoxycillin and mecillinam on the adhesion of Escherichia coli bacteria to human urinary tract epithelial cells: a preliminary study.

Attachment to mucous surfaces may be a prerequisite for bacteria colonizing these surfaces or invading underlying tissues. Subinhibitory amounts of ampicillin and amoxycillin but not mecillinam decreased the attachment of Escherichia coli bacteria to human uro-epithelial cells in vitro. No significant synergistic effect on the attachment by the antibiotics was obtained. The present report indicates a new parameter for the study of antibacterial actions of drugs.

Adhesiveness↗
PubMed1979

Experimental evidence of a decreased incidence of penicillin allergy through use of pure penicillins.

The results revealed the presence of high molecular weight impurities in commercially available penicillins, measured with a radioimmuno assay. The impurities had penicilloyl specificity and induced antibody formation in mice when the contaminated penicillin was administered in 50 mg/kg body weight daily for ten day periods with a 20 to 30 day interval. Penicillin of high purity similarly administered produced very few antibodies. Furthermore, experimentally contaminated penicillin given according to the same schedule caused IgE antibody formation against the penicilloyl moiety, while pure penicillin did not. These findings were explained by the weak immunogenicity of isologous penicilloylated serum albumin in rabbits both regarding the IgE and the IgG/IgM antibody formation compared to the immunogenicity of heterologous bovine serum albumin similarly penicilloylated.

Animals↗
PubMed1979

Immunotherapy in spring-time hay fever. A clinical and immunological study comparing two different treatment extract compositions.

In a study of the efficacy of two different treatment schedules for perennial immunotherapy, 47 adult patients with spring-time hay fever due to allergy against birch and other deciduous trees were randomly assigned to three treatment groups: one group received birch, alder and hazel allergen in Allpyral, another group received the same Allpyral mixture and in addition all relevant tree pollens in aqueous extract and a control group received no injections. For determination of antibody titres the radioallergosorbent test (RAST) and the ammonium sulphate precipitation (ASP) technique were used. Cellular responsiveness was studied by measuring birch pollen (BP) induced leucocyte histamine release in peripheral blood. The clinical and immunological response was similar in the two treated groups. Treated patients had less symptoms and a lower consumption of antihistamine tablets during the pollen season than the control group. Non-IgE BP antibodies and IgE antibodies recorded with the ASP technique increased after immunotherapy while RAST values did not change significantly. A decrease of RAST values from postseasonal values during the first year to preseasonal values in the following year was seen in all patient groups but was less pronounced in treated than in untreated patients. The decrease was more pronounced in patients with high RAST values of postseasonal sera than in patients with low RAST values. Cellular reactivity increased slightly during the first phase of therapy but returned to the pre-treatment level later. Clinical improvement was positively correlated to the percentage increase of non-IgE antibody titre and to the pre-treatment non-IgE/IgE antibody ratio. Patients with high preseasonal RAST titres or high cellular sensitivity tended to have more severe symptoms during the pollen season. It is concluded that a mixture of birch, alder and hazel is sufficient for immunotherapy in spring-term hay fever. It is obvious that changes of a single immunological variable do not account for the therapeutic results in immunotherapy.

Adult↗
PubMed1979

Immunological aspects of pyelonephritis.

Several virulence factors, such as O and K antigens and capacity to attach to uroepithelial cells, seem to be required for Escheria coli to cause acute pyelonephritis. These factors induce an immune response, however, which can modify the course and clinical expression of the infection. During acute pyelonephritis, autoantibodies to the Tamm-Horsfall protein increase. These antibodies, which probably are evoked by a cross-reaction noted between structures of E. coli LPS and the Tamm-Horsfall protein, may add to the renal tissue engagement in interstitial nephritis caused by bacterial pyelonephritis.

Acute Disease↗
PubMed1979

Antigens in penicillin allergy. III. Antigen and antibody levels in mice treated with pure and contaminated penicillins.

Using a radioimmunoassay, it was shown that commercially available ampicillin preparations often contain penicilloylated high molecular weight impurities. These possess immunological activities and stimulate penicilloyl-specific antibody formation in mice treated according to a therapeutic schedule. Using purified and experimentally contaminated preparations it was also found that exposure of the animals to Escherichia coli and Bordetella pertussis bacteria could increase the antibody formation to small amounts of impurities. In addition, penicilloylated antigen could be recorded in serum from treated animals. The antigen formed by penicilloylation in vivo, however, was very weak and did not induce much antibody formation when injected together with Freund's adjuvant in mice or rabbits.

Ampicillin↗