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Notes: The plant lectin concanavalin A (Con A) has been shown to induce basophil histamine release by an IgE-receptor-dependent process resembling that of anti-IgE-antibodies.In this study, the concentration-response for basophil histamine release from washed blood cells was analyzed in a population of blood samples from adults with a total plasma IgE content ranging from 〈 5 kU/l to 〉 18000 kU/l (n= 108), as well as 148 cord blood samples.The concentration-response-curves for anti-IgE in all adult blood samples were similar, despite the large variation in total plasma IgE - only the cord blood samples showed a decreased sensitivity. In contrast, the optimal concentration of Con A was inversely related to plasma IgE, and this relation was most pronounced in the adult blood samples.It is proposed that IgE-receptor-mediated histamine release may be dependent not only on the number of stimulatory, dimeric cross-links formed between IgE-receptors, but also on the molecular structure of the cross-linking agent.

Notes: Histamine release (HR) from washed human blood cells after challenge with the excretory-secretory antigens (ES) of the parasitic nematodes Toxocara canis and Ascaris suum was studied, employing a recently developed microfibre–based assay combined with hyperosmolar release media for maximal sensitivity.Blood samples were obtained from 30 patients suspected of parasite infection and 11 healthy volunteers serving as controls. Specific antibodies of IgE, IgG1 and IgG4 subclasses were determined by ELISA.Virtually no HR could be provoked by ES in the 11 controls. In contrast, HR was seen in 16 patients after challenge with T. canis ES and in II patients with A. suum ES. In the majority of these. HR was detectable after challenge with ES protein concentrations of less than 1 ng/ml. and the maximal HR obtained with ES was greater than that seen with optimal concentrations of anti-IgE.The HR after ES antigen challenge correla ed with the amount of specific IgE in patient plasma, and coincided with the presence of specific IgGi and IgG4.

Notes: Background Atopy is closely associated with the cellular T helper type-2 (Th2) phenotype, that is dominated by the pleiotrophic cytokine IL-4. The cellular source of IL-4 has yet to be determined, although basophils have been proposed. Eosinophils and mast cells are likely contenders investigated here, and the eosinophil-like leukaemia line AML14.3D10 is compared to eosinophils as an in vitro culturable model for eosinophils. Lectins can cross-link-specific surface glycoproteins and are found in the ingested (processed foods) and inhaled (airborne pollen grains) human environment. Therefore it is of interest to determine whether lectins can elicit the release of IL-4 from Th2-associated granulocytes other than basophils.Method This study investigated the ability of eosinophils, AML14.3D10 and mast cells to secrete preformed IL-4 in response to stimulation with lectins, and explored molecular mechanisms underlying the interaction.Results Purified eosinophils and basophils, and cultured mast cells and AML14.3D10 cells were incubated with 1 µm lectin. Agglutination was scored by microscopy. IL-4 secretion was measured by enayme-linked immunosorbent assay. Biotinylated lectins were used to determine binding to cells by flow cytometry and in lectin blots of sodium dodecyl sulphate (SDS) gels.Discussion Purified human eosinophils, AML14.3D10 cells and cultured mast cells secrete IL-4 with a pattern similar to that found in basophils when stimulated with a panel of reactive and unreactive lectins. The lectin SNA induces IL-4 secretion from mast cells and basophils, but not from eosinophils or AML14.3D10. Eosinophils appear to secrete only pre-formed IL-4, whereas mast cells may synthesize IL-4 on ligation with the lectin LCA. Lectins that agglutinate the granulocytes investigated do not necessarily induce secretion of IL-4. Lectins that elicit secretion of IL-4 bind more to eosinophils than unreactive lectins as determined by flow cytometry and lectin blotting of SDS gels.Conclusion As granulocytes with functions related to that of basophils, eosinophils, AML14.3D10 and cultured mast cells respond to stimulation with lectins similarly to basophils. This emphasizes the possibility that eosinophils and mast cells may be linked in their cellular heritage as the cellular partners, and lectins as ligands, may contribute to the maintenance of a Th2-favoured microenvironment that is thought to underlie the allergic march.

Notes: Mannan-binding protein (MBP) is a member of the collectins. These lectins are composed of polypeptide chains which contains a collagen-like region and a calcium dependent carbohydrate recognition domain (named a C-type CRD). MBP binds via the CRD to carbohydrate structures on microorganisms. MBP can activate the complement system when bound to carbohydrate. MBP is thus thought to play a role in the defence against microorganisms. The present report describes the ontogeny of MBP. The level of MBP increase during the first 3 months of life, at which time a stable level is reached, comparable to that seen in adults. On average, the level of MBP at term was 37% of the post 3-month level. Measurements on infants born prematurely showed a 3-fold increase in MBP concentration from the time of birth at around 30 weeks from conception to the 10th week of life.;

Notes: Cord blood samples were collected from a birth cohort of 2631 infants to elucidate the association between genetic and environmental factors and fetal production of IgE. The cord blood IgE values were treated both as a continuous and as a dichotomous variable in the statistical analyses. Multivariate analysis was used to control for confounding factors. Infants with single and biparental atopic heritage had higher IgE concentrations in cord plasma than children of parents without atopy. Multiple logistic regression analysis revealed a significant association to maternal allergic eczema or perennial rhinitis. The cord blood IgE concentration varied with month of birth with peaks in late autumn. This seasonal variation was not related to parental atopic disease. Boys had significantly higher levels of IgE and more often elevated IgE values (≥0.5 kU/1) than girls. Alcohol and caffeine consumption by the mothers during pregnancy were both significantly associated with elevated IgE concentration. There was also a relation between mothers prepregnant weight and elevated CB-IgE levels. No significant association was observed between maternal smoking and cord plasma IgE levels. The fact that many factors presumably not related to child allergy seem to influence the regulation of fetal IgE production, could explain the questionable value of cord blood IgE in predicting allergy in childhood.

Notes: The cellular branch of the immune defence in the newborn has been shown to differ from adults in a number of ways. This report presents new data on the functions of the histamine-sccreting cells of the newborn. Mast cells of the newborn were obtained from the human umbilical cord by enzymatic dispersion. The granules of the mast cells of the umbilical cord were found to contain both chymase and tryptase by immunohistochemical staining, and the presence of cell bound IgE on the mast cell surface was demon-strated by staining sections of umbilical cord with peeroxidase conjugated anti IgE. The enzymatic dispersion yielded 12, 660 mast cells per gram um-bilical cord (median), range 2, 500—60, 300 (n=48). The mast cells were found to constitute 3. 1 % of the total nucleated cells in the dispersate (median), range 1. 5—3. 8%. The histamine release from these cells was measured using a glass microfibre-based method. Both the umbilical cord mast cells and the cord blood basophils released histamine stimulated with anti-IgE. concanavalin A and the calcium ionophore A23187. In contrast to mast cells from adult tissue, the phorbol ester TPA was found to be an efficient secret agogue in both mast cells and basophils from the newborn. After maximal stimulation with anti-IgE and phorbol ester the quantity of histamine released per millilitre of blood was significantly higher in cord blood than in adult blood. The spontaneous histamine release from cord blood basophils was also significantly higher than from adult blood basophils. The mast cells found in the umbilical cord matrix and the cord blood basophils represent a readily available source of metabolically active histamine releasing cells for exploration of the role of histamine-secreting cells in newborn im-mune defence.

Notes: To study the human intestinal mast cell of children and adults, we combined a sensitive glassfibre-based histamine assay with the enzymatic and mechanical dispersion of surgical specimens or mucosal biopsies. The method yields between 1.2 × 103 to 4.6 × 103 mast cells/mg tissue constituting 1.2% to 5.3% of total cell count. The mast cell yield, however, depends on the intestinal tissue specimen used for dispersion. Aliquots containing 1500 mast cells per sample are sufficient for measuring significant amounts of histamine (± 0.15 ng histamine per sample), thus making it possible, to carry out approximately 75 tests for four mucosal biopsies of 10 mg each. The intestinal mast cell releases histamine in a dose-dependent manner on challenge with anti-IgE (6–600 U/ml), ionophore A23187 (0.25–1.0 μM), and Concanavalin A (0.7–25.0 μg/ml). The histamine release shows interindividual variation with a net histamine release between 0 to 2.5 ng/samples dependent on the secretatogue. In general, it is not necessary to passively sensitize the mast cells to obtain a sufficient histamine release response to anti-IgE challenge, indicating the presence of intact and functional cell-bound IgE. However, it is shown that four of 10 non-atopic intestinal mast cell samples could be passively sensitized with human plasma containing either mite- or grass-specific IgE without stripping off the IgE first. This indicates the presence of free and preserved Fc-receptors on the dispersed mast cells in some subjects. In addition, it is found that the phorbolester TPA increases the histamine release response to A23187 and turns anti-IgE non-responding mast cells into responding mast cells, but TPA alone at 2 to 16 ng/ml has no histamine releasing effect. In patients with anti-IgE responding mast cells no additional effect of TPA is seen. Finally, no substantial differences between mast cells of children and adults are demonstrated.

Notes: Basophil leukocytes from a non-atopic donor, who responded well to anti-IgE, were depleted of their native membrane-bound IgE by acid treatment and passively sensitized with plasma containing either Phleum pratense-, Dermatophagoides pteronysstnus- or dog dander- specific IgE obtained from 18 allergic children. Histamine release was then performed on the passively sensitized cells and the results were compared with those of bronchial provocation test (BPT), allergen-specific serum IgE (RAST), skin prick test (SPT), and conventional histamine release test (HR). A high coincidence rate was found between BPT, RAST and histamine release after passive sensitization (HR-PS), but compared to HR, it was lower. This could be because several of the patients had non-responding basophils (i.e. no release after challenge with anti-IgE) in the conventional histamine release asssay. The lower rate was not related to a lack of antigen-specific IgE, since after passive sensitization of basophils, anti-IgE and allergen provocation could induce release. It is concluded that plasma from allergic children with non-responding basophil leukocytes contain antigen-specific IgE capable of binding to Fc-receptors on the basophils of a non-atopic donor. In addition it was found that the plasma could change the cell reactivity (maximal histamine release) of the donor cells, since the amount of histamine released varied according to the plasma used for passive sensitization. The lack of histamine release response in some patients could be because their own membrane-bound IgE is unable to induce mediator release or, more likely, activation of one or more of the subcellular steps involved in the release is impaired.

Notes: In vitro formation of immune complexes was studied by 3H-serotonin release from human platelets by P. aeruginosa antigens in the presence of serum From 22 cystic fibrosis patients. chronically infected with mucoid P. aeruginosa (CF + P) and with a pronounced antibody response against these bacteria, and in 24 patients without P. aeruginosa (CF-P). All CF + P patients responded with 3H -serotonin release (16–34%), whereas CF-P patients released less than 15%. In the group of CF4-P patients the number of P. aeruginosa precipitins was correlated to the serotonin liter. Time courses indicated that SH-serotonin release was maximal between 2 and 5 min, and that no further release was observed up to 20 min. There was a gradual increase in 3H -serotonin release with higher platelet concentrations The response was not changed by complement inactivation. and fractionation of serum demonstrated that the serotonin release was dependent on the presence of the immuno-globulin fraction. These experiments support the suggestion of a type 111 reaction being invoked in the lung damage in CF + P patients and also suggest a possible involvement of serotonin in the inflammatory reaction during chronic P. aeruginosa lung infection.