Enhancement of IgE-mediated histamine release from human basophils by immune-specific lymphokines.

Human leucocytes (basophils) release histamine when exposed to ragweed antigen E or anti-IgE. The present study shows that when leucocytes from BCG-positive donors are first incubated with PPD and then challenged with anti-IgE, histamine release is enhanced. In contrast, when leucocytes from BCG-negative donors are incubated with PPD and then challenged with anti-IgE there is no enhancement of histamine release. The enhancement of histamine release was detected within 24 hr after addition of PPD, but was maximal at 48 to 72 hr. Supernatant fluids collected from these leucocyte cultures revealed the presence of a soluble mediator(s) which, when incubated with leucocytes from BCG-negative donors, enhanced the release of histamine. Examination of the supernatant fluids from BCG-positive leucocyte cultures stimulated with PPD showed a correlation between histamine-release enhancing activity and interferon. Treatment of the culture fluids at pH 2.0 abolished the anti-viral activity, indicating that the interferon was of the type II or ''immune'' class. The same treatment only partly abolished the histamine-release enhancing activity. It is concluded that immune-specific stimulation of leucocytes results in the release of soluble mediators that are capable of enhancing IgE-mediated histamine release.     

Enhancement of histamine release from human basophils pretreated with different sialidases

Histamine release from human basophils was investigatedin vitro after removal of cell membrane sialic acid by three different sialidases. Pretreatment of the cells with sialidases fromCl. Perfringens, V. Cholera orInfluenza virus A ₂ enhanced histamine release induced by subsequent stimulation of the cells with anti-IgE or the plant lectin Concanavalin A and caused a shift to the left of the dose-response curve for anti-IgE. The enhanced histamine release was reflected in a increased calcium sensitivity, thus suggesting that cell membrane sialic acid might be involved in the calcium fluxes preceeding histamine release. In higher doses the sialidase fromCl. Perfringens caused the cells to release histamine by itself, whereas the sialidases fromV. Cholera andInfluenza virus A ₂ in high does inhibited the cell response to Concanavalin A.     

Virus enhances histamine release from human basophils

Histamine release from human basophil leukocytes was triggered byStaph. aureus or by complement activation caused by endotoxins isolated fromE. coli or Salmonella bacteria. Influenza A virus was found to enhance the mediator release and the effects was caused by synergism, since the virus itself did not release histamine. The potentiating effect of the virus was abolished by a potent neuraminidase inhibitor. Furthermore, a purified neuraminidase preparation obtained fromVibrio cholerae caused a similar potentiating effect, which was also abolished by the neuraminidase inhibitor. These findings indicate that the neuraminidase on the surface of influenza A virus is responsible for the potentiating effect of the virus on basophil histamine release.     

Unique serum requirement for histamine release from human basophils.

Basophil histamine release in a patient with an IgE-mediated seminal plasma allergy had a requirement for serum. Washed leukocytes, in the absence of serum, released little histamine on challenge with seminal plasma antigen. The addition of serum markedly enhanced the release. However, serum had only a mild effect on ragweed antigen induced histamine release from the same cells of this individual. Serum from normal donors was equally effective as autologous serum. Heating the serum and treating it with mercaptoethanol did not destroy this activity. The serum effect was unique in that another patient with seminal plasma allergy did not demonstrate this phenomenon. It is postulated that the effect of the serum is to stabilize the antibody-antigen step at the basophil surface.     

Enhancement of murine macrophage binding of and response to bacterial lipopolysaccharide (LPS) by LPS-binding protein.

We have studied the effects of highly purified rabbit lipopolysaccharide (LPS)-binding protein (LBP) on the ability of murine bone marrow-derived macrophages to respond to bacterial LPS. Macrophage responses studied include the secretion of tumor necrosis factor alpha, production of arginine-derived nitrite (NO2-), and killing of an intracellular pathogen, Leishmania enriettii. Macrophages from either CBA or LPS-hyporesponsive C3H/HeJ mice exhibited significantly greater sensitivity to LPS in the presence of LBP. Furthermore, both CBA and C3H/HeJ macrophages demonstrated an LBP-dependent enhancement of LPS binding. These results suggest that C3H/HeJ macrophages are capable of binding LPS-LBP complexes and support the hypothesis that hyporesponsiveness in this strain involves a step subsequent to LPS binding. Furthermore, these findings provide additional evidence of the important role played by the acute-phase plasma protein LBP in modifying host response to LPS.     

Concanavalin A induced histamine release from human basophils in vitro.

The site of interaction for concanavalin A (Con-A)-induced histamine release from human basophils was studied in vitro. Blocking the epsilon one determinant (D leads to 1) of IgE with high concentrations of monomer (Fab) anti-Depsilon1 does not significantly inhibit the quantity of histamine released by suboptimum concentrations of Fc specific anti-IgE. This indicates that the monomer anti-Depsilon1 does not have the capacity to sterically hinder the bridging of all of the determinants in the Cepsilon3 and Cepsilon4 domains (Fc'-epsilon-region) of IgE. The monomer anti-Depsilon1 does effectively inhibit release induced by suboptimum concentrations of Con-A. The data indicate that for suboptimum concentrations, Con-A activation is IgE mediated and takes place in the proximity of Depsilon1 and not at the membrane receptor for IgE.     

Hyperosmolarity selectively enhances IgE-receptor-mediated histamine release from human basophils

Increased osmotic pressure has been reported to cause non-cytotoxic histamine release (HR) from human basophils, as well as a potentation of HR induced by anti-IgE. In this study, the effects of hyperosmolar Na–K-acetate (300–600 mOsm/kg H₂O) on HR was studied in washed human blood cells from newborns, adult volunteers and patients with severe atopic dermatitis. These three patient groups represesented 3 very distinct populations with respect to total plasma IgE content, medians were <0.2 IU/ml, 20.5 IU/ml and 2508 IU/ml, respectively. Increasing osmolarity to 500 mOsm/kg H₂O caused little HR in the absence of other stimuli, whereas at 600 mOsm/kg H₂O a significant increase in spontaneous HR was seen. The HR induced by anti-IgE and Concanavalin A, acting through the IgE-receptor, was increased approximately twofold at 500 mOsM/kg H₂O. Responses were highly correlated to results at 300 mOsm/kg H₂O. The use of 600 mOsm/kg H₂O buffers caused a further increase in most, but not all blood samples. The potentiation of IgE-receptor-mediated HR when using hyperosmolar media was clearly independent of plasma IgE contents, and did not change the concentration-response to anti-IgE. In contrast, HR induced by the IgE-receptor-independent stimuli, Formyl-met-leu-phe and calcium ionophore A 23187, were not enhanced at all by incrased osmotic pressure. We conclude, that hyperosomolar media selectively enhance IgE-receptor-mediated HR. The use of hyperosmolar media may therefore be beneficial in a diagnostic application of washed blood HR assays use in allergy diagnosis.     

Inhibition of histamine release from human basophils in vitro by calmodulin antagonists

Calmodulin is a ubiquitous and versatile Ca2+-binding protein that plays a pivoting role in cellular metabolism. We have investigated the possibility that calmodulin plays a role in immediate hypersensitivity reactions by evaluating the effects of two agents, trifluoperazine dihydrochloride (TFP) and the sulfonamide derivative N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) which selectively bind to calmodulin. TFP and W-7 cause a dose-dependent inhibition of histamine secretion from human basophils in vitro induced by several immunological (i.e., antigen and anti-IgE) and nonimmunological (i.e., formyl-methionine-containing peptide and the Ca2+ ionophore A23187) stimuli. These results indicating that two specific calmodulin antagonists are potent inhibitors of the secretory response of human basophils support the hypothesis that calmodulin may play a role in the control of the release of preformed mediators from human inflammatory cells.     

The effect of short-term immunotherapy with Pollinex on anti-IgE and antigen-induced histamine release from sensitive human basophils

Anti-IgE and antigen-induced histamine release from basophils isolated from 30 atopic patients sensitive to grass pollen allergens was evaluated. The studies were made before and after short-term immunotherapy with glutaraldehyde-pollen-tyrosine adsorbate (Pollinex). It was shown, that after immunotherapy a significant drop in anti-IgE and specific antigen-induced histamine release from isolated basophils occurs. The investigations confirm that the diminution of the target cell sensitivity and releasability may be one of the effects of specific immunotherapy.     

Influence of bronchial allergen challenge on histamine release by human basophils

BACKGROUND: Basophils can be primed by cytokines such as interleukin (IL) -3, IL-5 or granulocyte macrophage-colony stimulating factor (GM-CSF). It has been described that the concentrations of these cytokines are enhanced at sites of allergic inflammation as well as systemic in allergic asthma. OBJECTIVE: To investigate the priming status of basophils as detected by thapsigargin-induced histamine release during bronchial allergen challenge. METHODS: Ten subjects allergic to house dust mite were challenged via an aerosol delivery system. Spontaneous leucocyte histamine release as well as histamine release induced by various stimuli was measured in vitro at several time points. In addition, lung function parameters, serum IL-5 and blood eosinophil counts were evaluated. RESULTS: We found no effect of bronchial allergen challenge upon spontaneous leucocyte histamine release, nor upon histamine release induced by anti-immunoglobulin (Ig) E, house dust mite extract, C5a, fMLP, IL-3, PMA+ thapsigargin or IL-3+ thapsigargin. However, the priming status of basophils as measured by thapsigargin-induced histamine release was enhanced at 24 h after bronchial allergen challenge. Analysis of the individual data showed a heterogeneous initial response (30 min, 6 h) followed by a predominant increase at 24 h after allergen challenge. This increase in the thapsigargin-induced histamine release correlated with the increase in serum IL-5 levels at 24 h after allergen challenge. CONCLUSION: The priming status of human basophils as measured by thapsigargin-induced histamine release is enhanced 24 h after allergen challenge.     

Recombinant human interleukin-1 beta causes histamine release from human basophils

Histamine releasing factors (HRFs) have been demonstrated to be secreted by human lymphocytes and monocytes (alveolar macrophages); however, none has been purified to date. Because of the similarity of our HRF to the physical chemical properties of interleukin-1 (IL-1) and tumor necrosis factor (TNF), we have assessed the ability of preparations of IL-1 and TNF to cause basophil histamine release (HR). Human recombinant pro-IL-1 beta, recombinant mature IL-1, and, to a lesser extent, human recombinant TNF caused significant HR from a subpopulation of donor basophils. The pro-IL-1 beta elicited a dose response between 40 and 800 ng/ml; higher concentrations were inhibitory. Approximately 30% of subjects tested are responsive to either mature IL-1 or TNF. These share the same responder subset, but the magnitude of the TNF response is considerably less. A response to the pro-IL-1 was restricted to those subjects with prominent HR to anti-IgE; the response to mature IL-1 and TNF was unrelated to the response to anti-IgE. As in other functional assays, the pro-IL-1 is 50- to 100-fold less potent than mature IL-1, and unlike human HRF, it is highly unstable and rapidly loses activity. Mononuclear cell-derived HRF differs in physicochemical properties from IL-1 or TNF; nevertheless, it appears likely that a variety of cytokines may possess histamine-releasing capability.     

Regulation of human basophil activation. I. Dissociation of cationic dye binding from histamine release in activated human basophils.

Human basophil activation was demonstrated by histamine release (HR) and by the decrease of the toluidine blue-positive basophils (TB+). In four experimental systems, TB+ number decreased in the absence of HR (1) in basophils from atopic subjects stimulated by allergen concentrations below the threshold for HR, (2) in basophils sensitized by anti-2,4-dinitrophenyl IgE stimulated by noncovalently linked 2,4-dinitrobenzene sulfonic acid-human serum albumin (also, the threshold for decrease of TB+ required lower concentrations of sensitizing anti-2,4-dinitrophenyl IgE than for HR), (3) in low Ca++ medium, and (4) in the presence of the Na+/H+ exchanger, monensin. These results suggest that (1) there is a lower threshold for TB+ decrease than for HR in allergen concentration, number of membrane IgE molecules, and number of IgE cross-linkings; moreover, external Ca++ requirement is lower for decrease of TB+ than for HR and (2) TB+ decrease reflects either granule exocytosis or, in the absence of HR, biochemical changes (most probably cation exchanges) altering the interaction of the basic dye with the granules. Thus, monitoring decrease in TB+ allows detection of basophil activation in the absence of HR.     

Immunologic histamine release from isolated human basophils during specific immunotherapy

Anti-IgE- and antigen-induced histamine release from basophils isolated from 20 atopic patients sensitive to grass pollen allergens was evaluated. The studies were made before and after short-term immunotherapy with Pollinex. It was shown, that after hyposensitization a significant decrease on anti-IgE and specific antigen-induced histamine release from basophils occurs.This work was supported by the Polish Academy of Sciences (Grant No. 10.5).     

Inhibition of IgE-mediated histamine release from human basophils and mast cells by fenoterol

Fenoterol, a beta 2-adrenergic agonist recently introduced to treat asthmatic disorders, inhibits antigen-induced histamine release from human basophil leukocytes and lung mast cells in a dose-dependent fashion. The dose-response inhibition curve is paralleled by a fenoterol-induced increase in the cAMP levels of human leukocyte preparations. The relationship between the effect of fenoterol and cAMP level is supported by the finding that the beta 2-adrenergic agonist only inhibits the first stage of antigen-induced histamine release and not the release caused by the Ca2+ ionophore, A23187. Propranolol, a competitive antagonist of beta 2-adrenergic receptor, blocks the inhibition of release and the cAMP accumulation caused by fenoterol. Finally, theophylline, a cAMP phosphodiesterase inhibitor, synergistically potentiates the inhibitory effect of fenoterol on histamine release and the accumulation of cAMP. These data suggest that fenoterol may modulate the in vivo release of the mediators of immediate hypersensitivity reactions via the activation of beta 2-adrenergic receptor linked to adenylate cyclase on human basophils and mast cells.     

Role of protein kinase C in histamine release from human basophils

In this study, we investigated the role of calcium and phospholipid-dependent protein kinase (protein kinase C, PKC) in the modulation of histamine release from human basophils. A novel and potent inhibitor of PKC, K-252a, inhibited the release of histamine induced by anti-IgE in a dose-dependent manner with ID50 (the dose required for 50% inhibition of histamine release) of 2.2 x 10(-8) M. Histamine release stimulated with 12-0-tetradecanoyl-phorbol-13-acetate(TPA) was also suppressed by K-252a with maximal inhibition of 48.0 +/- 9.3% at 10(-7) M. In contrast, K-252a did not inhibit the release of histamine in response to FMLP and ionophore A23187. Another inhibitor of PKC, H-7, exhibited a dose-dependent inhibition of anti-IgE-induced histamine release with ID50 of 8.6 x 10(-4) M. H-8 and HA1004, which closely resemble H-7 in chemical structure but are less potent in inhibiting PKC, did not inhibit histamine release stimulated with anti-IgE, but rather enhanced the release at higher concentrations. These results strongly suggest that PKC activation plays a crucial role in the mediation of IgE-mediated histamine release from human basophils.     

Enhancement by a serum factor of immunoglobulin-mediated histamine release from human leukocytes.

When serum was fractionated on Sephadex G-200, the material eluted in the second and thir major peaks had a very pronounced capacity to enhance IgE- as well as IgG-mediated histamine release from the leukocytes of both normal and allergic donors. Unseparated serum on the other hand had a low capacity to stimulate anti-IgE-induced histamine release. Besides resulting in a higher histamine release, pretreatment with serum fractions also increased the rate of histamine release. Further purification revealed that the stimulating activity of the material in the second peak was mediated by a trypsin-sensitive component, probably active in low concentration.     

Histamine release from human basophils by the insect allergen Chi t I.

Hemoglobins of the Diptera species Chironomus thummi thummi (Chi t I) are potent inhalant allergens. Chi t I-specific histamine release was measured by a new radioimmunoassay in whole human blood taken from 20 sensitized patients, 11 exposed nonsensitized probands, and 11 nonexposed controls. The sensitized patients, who all had positive skin tests and radioallergosorbent test results with Chi t I, showed a significantly higher histamine release than the two other groups. However, within the patient group, the percentage of released histamine did not correlate with the intensity of the skin test response or the concentration of Chi t I-specific IgE antibodies. Our results demonstrate that this method is a sensitive and specific in vitro test for evaluation of IgE-mediated sensitization.