| 1. |
- Gustafsson, Lars, et al.
(författare)
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Infectious disease, reproductive effort and the cost of reproduction in birds
- 1994
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Ingår i: Philosophical transactions of the Royal Society of London: Series B. ; :346, s. 1655-1658
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Reproductive effort can have profound effects on subsequent performance. Field experiments on the collared flycatcher (Ficedula albicollis) have demonstrated a number of trade-offs between life-history traits at different ages. The mechanism by which reproductive effort is mediated into future reproductive performance remains obscure. Anti-parasite adaptations such as cell-mediated immunity may probably also be costly. Hence the possibility exists of a trade-off between reproductive effort and the ability to resist parasitic infection. Serological tests on unmanipulated collared flycatchers show that pre-breeding nutritional status correlates positively with reproductive success and negatively with susceptibility to parasitism (viruses, bacteria and protozoan parasites). Both immune response and several indicators of infectious disease correlate negatively with reproductive success. Similar relations are found between secondary sexual characters and infection parameters. For brood-size-manipulated birds there was a significant interaction between experimentally increased reproductive effort and parasitic infection rate with regard to both current and future fecundity. It seems possible that the interaction between parasitic infection, nutrition and reproductive effort can be an important mechanism in the ultimate shaping of life-history variation in avian populations.
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| 2. |
- Akhiani, Aliasghar, 1957, et al.
(författare)
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Immunological cross reactivity between Schistosoma mansoni and cholera toxin
- 1997
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Ingår i: Parasite Immunol. ; 19:8, s. 355-61
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Tidskriftsartikel (refereegranskat)abstract
- Intranasal administration of schistosome antigens in combination with appropriate adjuvant may be an effective route for immunization against schistosomes, since the lungs represent an important site of elimination of schistosomulae. Our previous studies have shown that in mice intranasal administration of cholera toxin (CT) before infection with Schistosoma mansoni results in an enhancement of the worm burden in comparison to nontreated infected animals. In the present study, it was shown that mice treated intranasally with CT displayed high numbers of schistosome-reactive IgM-secreting cells in the spleen as well as high levels of schistosome-reactive serum IgM antibodies, whereas no significant immunological response against two other antigens, ovalbumin (OVA) or keyhole limpet haemocyanin (KLH) was noted. Sera from mice treated intranasally with CT recognized a 22 kDA antigen on SWAP blots. This band was not demonstrable after absorption of the sera with SWAP. These findings indicate a possible cross reactivity between cholera toxin and schistosome antigens. Further analysis by Western blot revealed that a 22 kDa antigen was detected on CT blots by sera from mice and humans infected with S. mansoni. This band was not demonstrable after absorption of the mouse or the human sera with CT. The 22 kDa cross reactive antigen was heat-stable. The antibodies against the 22 kDa antigen were only found within the IgM class but not within other Ig isotypes. Our findings also indicate that the 22 kDa antigen detected by anti-S. mansoni antibodies represents the A1 fragment of the cholera toxin.
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| 3. |
- Dahlgren, Ulf, 1953, et al.
(författare)
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Expression of a dietary protein in E. coli renders it strongly antigenic to gut lymphoid tissue.
- 1991
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Ingår i: Immunology. - 0019-2805. ; 73:4, s. 394-7
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria that colonize the intestinal mucosa elicit a strong mucosal immune response, whereas food antigens such as ovalbumin are very weakly immunogenic to the gut-associated lymphoid tissue. This may either be due to special physico-chemical properties of bacterial substances versus proteins from animals and plants, or to stimulating properties of the bacteria on, e.g., antigen presentation, rendering all substances contained within bacteria antigenic. To test these hypotheses, ovalbumin was expressed in wild-type Escherichia coli and germ-free female rats were colonized with this strain. The systemic and mucosal antibody response of these rats was compared with that of rats given large amounts of dietary ovalbumin. Biliary IgA antibodies, which reflect the local IgA antibody production in the intestine, were only found in the rats colonized with ovalbumin-synthesizing E. coli. IgG antibodies in the bile were also only seen in these rats. We conclude that mucosal immunogenicity depends on the context in which a protein is presented to the gut-associated lymphoid tissue, rather than to special antigenic characteristics of the protein in itself.
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| 4. |
- Greiff, Lennart, et al.
(författare)
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Effects of topical platelet activating factor on the guinea-pig tracheobronchial mucosa in vivo
- 1997
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 160:4, s. 387-391
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Tidskriftsartikel (refereegranskat)abstract
- Platelet activating factor (PAF) has been reported to produce a variety of airway effects including epithelial damage and increased airway-lung absorption of hydrophilic tracers. The present study examines effects of PAF on the guinea-pig tracheobronchial mucosa in vivo. Vehicle with and without PAF (4.0 and 8.0 nmol) was superfused onto the tracheobronchial mucosa. The levels of 125I-albumin, previously given intravenously, were determined in tracheobronchial lavage fluids as an index of mucosal exudation of plasma. The mucosa was also examined by scanning electron microscopy. In separate animals, 99mTc-DTPA (a low molecular weight, 492 Da, hydrophilic tracer) was superfused onto the mucosal surface through an oro-tracheal catheter, together with vehicle or PAF (8.0 nmol). A gamma camera determined the disappearance rate of 99mTc-DTPA from the airways as an index of mucosal absorption. PAF produced dose-dependent mucosal exudation of plasma up to 20-fold greater than control (P < 0.001). However, PAF did not damage the epithelium and the absorption ability of the airway mucosa was unaffected. The results, in contrast to previous reports, suggest that PAF may not readily damage the airway mucosa even at large exudative doses of the agent. The present finding support the view that the plasticity of the epithelial junctions allows the creation of valve-like paracellular pathways for unidirectional clearance of extravasated plasma into the airway lumen. We suggest that endogenous PAF may participate in first line respiratory defence reactions by causing lumenal entry of bulk plasma without harming the epithelium.
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| 5. |
- Lodinová-Zádníková, R, et al.
(författare)
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The antibody response in breast-fed and non-breast-fed infants after artificial colonization of the intestine with Escherichia coli O83.
- 1991
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Ingår i: Pediatric research. - : Springer Science and Business Media LLC. - 0031-3998 .- 1530-0447. ; 29:4 Pt 1, s. 396-9
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Tidskriftsartikel (refereegranskat)abstract
- The local and systemic antibody response after oral administration of a nonenteropathogenic type 1 fimbriated Escherichia coli O83 strain was followed in nine breast-fed and eight formula-fed infants during their first 15 wk of life. Five breast-fed and six formula-fed infants were followed as controls. E. coli O83 was detected in the stools of colonized infants from d 2 after colonization and persisted in the intestine for up to 26 wk. The percentage of children successfully colonized with E. coli O83 was higher among breast-fed than among formula-fed colonized infants. Also, the O83 bacteria isolated from the breast-fed children had a higher capacity to attach to colonic epithelial cells of the HT-29 cell line than those isolated from bottle-fed infants. E. coli O83 IgA and IgM antibodies estimated by ELISA were significantly elevated in the saliva of colonized as compared with control infants 2-7 wk after colonization. IgA antibodies against O83 were also higher in the stool of colonized formula-fed infants than in formula-fed controls. The results suggest that the mucosal immune system of the newborn infant can be triggered early to produce specific antibodies against bacteria colonizing the intestine.
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| 6. |
- Strannegård, Inga-Lisa, 1937, et al.
(författare)
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Prevalence of allergy in children in relation to prior BCG vaccination and infection with atypical mycobacteria.
- 1998
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Ingår i: Allergy. - 0105-4538. ; 53:3, s. 249-54
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Tidskriftsartikel (refereegranskat)abstract
- By influence on the Th1/Th2 cell balance, infectious agents may affect the development of atopic allergy. In this study, we investigated whether previous BCG vaccination or infection with atypical mycobacteria might be related to the development of atopic disease. The study, which involved skin testing with mycobacteria and answers to a questionnaire for more than 6000 children in Sweden, revealed a low prevalence of allergy among BCG-vaccinated children who were immigrants or adopted from other countries. Vaccinated children born in Sweden, however, did not have significantly lower allergy prevalence than age-matched, unvaccinated children. Furthermore, the overall frequencies of skin-test reactivity to the atypical mycobacteria M. avium and M. scrofulaceum were higher rather than lower in allergic than in nonallergic children. By contrast, there was a tendency toward a lower frequency of more strongly positive skin reactions (> or = 10 mm) to mycobacteria in allergic than in nonallergic children. These findings do not support the hypothesis that early mycobacterial infections have a suppressive effect on the development of atopic disease. Earlier findings of an apparent association between atopy and lack of previous mycobacterial infection may possibly be explained by a relatively decreased ability of atopic patients to mount strong Th1 cell-mediated immune responses.
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| 7. |
- Leickt, Lisa, et al.
(författare)
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Affinity screening for weak monoclonal antibodies
- 1998
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Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 220:1-2, s. 19-24
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Tidskriftsartikel (refereegranskat)abstract
- When selecting for monoclonal antibodies of a desired affinity, affinity chromatography can be a feasible alternative. This is of particular interest when low affinity monoclonal antibodies (dissociation constant (Kd) > 10(-4) M) are screened, as they are not easily recognised by traditional immunoassay procedures. In this study we have evaluated this approach by monitoring low affinity monoclonal antibodies on high performance liquid affinity chromatography columns with oligosaccharides, dinitrophenol and digoxin as immobilised antigen. Crude monoclonal antibodies in ascites or cell culture supematants, directed against these antigens, were retarded or adsorbed according to affinity or avidity on the antigen columns. Based on antibody retention, we were able to select hybridomas with the desired low affinity characteristics.
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| 8. |
- Mattsby-Baltzer, Inger, 1949, et al.
(författare)
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IL-1beta, IL-6, TNFalpha, fetal fibronectin, and endotoxin in the lower genital tract of pregnant women with bacterial vaginosis.
- 1998
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Ingår i: Acta obstetricia et gynecologica Scandinavica. - : Wiley. - 0001-6349. ; 77:7, s. 701-6
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Tidskriftsartikel (refereegranskat)abstract
- In our studies on women with bacterial vaginosis (BV) in early pregnancy a strong association has been found between BV and the levels of endotoxin or interleukin-1alpha (IL-1alpha) in the lower genital tract. In the present study we investigated if an association could be found between BV and other cytokines (IL-1beta, IL-6, tumor necrosis factor alpha, TNF) or fetal fibronectin (FFN). The cytokine-inducing capacity of endotoxins present in the cervical mucus was explored in a monocytic cell assay.Cervical mucus or cervicovaginal fluid was collected from women with (BV) and without BV (nonBV) attending a family planning unit for first trimester abortion. The concentrations of IL-1beta, IL-6, TNF and FFN were determined by quantitative enzyme immunoassays. TNF was determined in 63 women (BV, n=25) out of whom 37 (BV, n=11) were analyzed for IL-1beta and the remaining 26 for IL-6 (BV, n=14). FFN was determined in another 36 women (BV, n= 19). The cytokine-inducing capacity of endotoxin-containing cervical mucus and purified endotoxin of Prevotella bivia were studied by an in vitro cell assay using a human monocytic cell line (THP-1).IL-lbeta and IL-6 were found in almost all women. The levels of IL-1beta, but not IL-6, TNF or FFN, were significantly increased in women with BV compared with the nonBV women (p<0.05). Purified endotoxin from P. bivia, and cervical mucus from BV women containing high levels of endotoxin were able to induce a cytokine response (IL-6) in monocytic cells in vitro.BV is associated with increased levels of IL-1beta in the lower genital tract of pregnant women in the first trimester. The ability of BV-associated endotoxins to induce cytokine production in monocytic cells may partly explain the increased IL-1beta levels.
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| 9. |
- Greiff, Lennart, et al.
(författare)
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Effects of hydrogen peroxide on the guinea-pig tracheobronchial mucosa in vivo
- 1999
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Ingår i: Acta Physiologica Scandinavica. - : Wiley. - 0001-6772 .- 1365-201X. ; 165:4, s. 415-420
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Tidskriftsartikel (refereegranskat)abstract
- Lumenal entry of plasma (mucosal exudation) is a key feature of airway inflammation. In airways challenged with histamine-type mediators and allergen the mucosal exudation response occurs without causing epithelial derangement and without increased airway absorption. In contrast, reactive oxygen metabolites may cause mucosal damage. In this study, involving guinea-pig airways, we have examined effects of H2O2 on airway exudation and absorption in vivo. Vehicle or H2O2 (0.1 and 0.5 M) was superfused onto the tracheobronchial mucosal surface through an oro-tracheal catheter. 125I-albumin, given intravenously, was determined in tracheobronchial tissue and in lavage fluids 10 min after challenge as an index of mucosal exudation of plasma. The tracheobronchial mucosa was also examined by scanning electron microscopy. In separate animals, 99mTc-DTPA was superfused 20 min after vehicle or H2O2 (0.1 and 0.5 M) had been given. A gamma camera determined the disappearance rate of 99mTc-DTPA from the airways as an index of airway absorption. The high dose of H2O2 (0.5 M) produced epithelial damage, increased the absorption of 99mTc-DTPA (P < 0.001), and increased the exudation of plasma (P < 0.001). Notably, it appeared that all extravasated plasma had entered the airway lumen within 10 min. These data demonstrate that H2O2 differs from exudative autacoids such as histamine by causing both epithelial damage and plasma exudation responses. These data also agree with the view that the epithelial lining determines the rate of absorption and is responsible for the valve-like function that allows lumenal entry of extravasated bulk plasma without any increased inward perviousness.
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| 10. |
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