Modulation of human basophil histamine release by hemopoietic growth factors

To determine what kinds of CSF modulate human basophil function, recombinant or purified hemopoietic growth factors were tested for the effect on histamine release from basophils. Both granulocyte (G)-macrophage (M) CSF and IL-3 markedly enhanced histamine release upon stimulation with anti-IgE in a dose-dependent manner (maximal enhancement 25.5% by GM-CSF and 30.8% by IL-3 as expressed as percent increase against total cellular histamine content), whereas G-CSF, M-CSF, and IL-4 had no effect. Enhancing action of these factors was still observed in the highly enriched basophil population, suggesting that this action was not via contaminating cells. Enhancement of histamine release by both factors was not necessarily IgE mediated, because they also amplified histamine release upon stimulation with FMLP and ionophore A23187. The enhancement by both factors was temperature dependent, and took place rapidly and reached plateau levels in 15 min. GM-CSF and IL-3 achieved the similar plateau level of augmentation and no additive effects were observed between them. This finding suggests that they enhance histamine release by sharing the same pathway in the release reaction.     

Possible role of calmodulin in the control of histamine release from human basophil leukocytes

We investigated the possible role of calmodulin (CaM) in the control of histamine release from human basophil leukocytes using several CaM antagonists. Trifluoperazine (TFP) (10(-6)-2 X 10(-5) M), pimozide (10(-6)-1.5 X 10(-5) M), chlorpromazine (CPZ) (10(-5)-10(-4) M) and promethazine (PMZ) (2 X 10(-5)-10(-4) M) inhibited in vitro histamine secretion from human basophils induced by several immunological (antigen, anti-IgE, and formyl-L-methionyl-L-leucyl-L-phenylalanine: f-met peptide) and nonimmunological (Ca2+ ionophore A23187 and the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate: TPA) stimuli. Trifluoperazine sulfoxide (TFP-S) and chlorpromazine sulfoxide (CPZ-S), which have very low affinity to CaM, had practically no inhibitory effect on histamine release from human basophils. The inhibitory effect of TFP could be made irreversible by irradiating the cells with UV light. A sulfonamide derivative, the compound N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) (2.5 X 10(-5)-2 X 10(-4) M), which selectively binds to CaM, inhibited the release of histamine from basophils. In contrast, the chloride deficient analogue, W-5, which interacts only weakly with CaM, had practically no inhibiting effect. The IC50 for enzyme release by a series of eight CaM antagonists was closely correlated (r = 0.91; p less than 0.001) with the CaM specific binding, supporting the concept that these agents act by binding to CaM and thereby inhibiting histamine release. TFP and W-7 inhibited histamine release in the absence and in the presence of increasing concentrations of extracellular Ca2+. These results emphasize the possible role of CaM in the control of histamine secretion from human basophils.     

Stimulation of basophil and rat mast cell histamine release by eosinophil granule-derived cationic proteins

Major basic protein (MBP), an arginine-rich basic polypeptide that constitutes the crystalloid core of the large specific eosinophil granule, has previously been shown to stimulate noncytolytic histamine release from human basophils and rat mast cells by an IgE-independent mechanism. Two additional basic polypeptides present in eosinophil granules, eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN), were examined for similar activity in the present study. Acid-solubilized eosinophil granules were fractionated by chromatography on a Sephadex G-50 column. Incubation of basophil-containing human mononuclear cells with the individual column fractions demonstrated that histamine release occurred only with the fractions that contained MBP. The selectivity of the basophil response for MBP was confirmed by using equimolar concentrations of purified MBP, ECP, and EDN. In contrast, both MBP and ECP, but not EDN, stimulated histamine release from purified rat peritoneal mast cells. Reduction and alkylation of the MBP molecule diminished the response of human basophils to MBP but enhanced the potency of the molecule with rat mast cells. The distinct potency of MBP as a stimulus for histamine secretion from human basophils suggests that eosinophil release of MBP may be a specific event in the augmentation of immediate hypersensitivity reactions and other disorders characterized by eosinophilia.     

Effect of synthetic cyclic nucleotides on immunologic histamine release from calf granulocytes.

Sensitized bovine granulocytes release histamine when exposed to specific antigens. A unique modulation of histamine release by adrenergic agents has been shown in the bovine; beta-adrenergic agonists enhance and alpha-adrenergic agonists inhibit histamine release. This is an opposite response to that reported in other species. The present study was undertaken to determine the possible relationship between cyclic nucleotides and adrenergic agents in this species. Dibutyryl cAMP enhanced antigen-induced histamine release over the complete concentration range tested (10(-6)--10(-3)M); it also overcame, in a dose-dependent manner, the inhibition of antigen-induced histamine release produced by 10(-4) M phenylephrine. The 8-bromo cGMP AND 0-MONOBUTYRYL CGMP had no significant effect on antigen-induced histamine release nor did 8-bromo-cGMP have any significant effect on the enhancement of histamine release produced by 10(-4) M dibutyryl cAMP. These findings suggest that only cAMP has a role in the modulation of antigen-induced histamine release from bovine granulocytes.     

Demonstration of Fcgamma receptors on human basophil granulocytes.

Fcgamma receptors were detected on human basophil granulocytes. The mononuclear cell fraction of human peripheral blood was incubated with heat-aggregated human IgG (HGG) followed by 125I-anti-HGG. Autoradiography of the cells showed that the majority of basophil granulocytes gave a significant number of grains. Basophils were not labeled by preincubation of the same cells with monomeric HGG followed by 125I-anti-HGG. However, the binding of aggregated HGG to basophils was inhibited by the presence of a high concentration of monomeric HGG or its Fc fragment but not by the Fab fragment. Evidence was obtained that Fcgamma receptors are distinct from IgE receptors on the same cells: i) Saturation of basophils with IgE did not affect the binding of aggregated HGG to the cells. ii) Preincubation with and the presence of aggregated HGG failed to affect the binding of 125I-IgE to basophils, or to block passive sensitization of the cells with IgE antibodies. iii) The Fcgamma receptors did not co-cap with IgE receptors. Aggregated HGG failed to induce histamine release from basophils even in the presence of D2O. It was also found that the presence of aggregated HGG on basophils did not modulate IgE-mediated histamine release from the cells.     

Inhibition of basophil histamine release by anti-inflammatory steroids. II. Studies on the mechanism of action

The glucocorticosteroids inhibit the IgE-dependent release of histamine by human basophils with an order of potency that very closely parallels that found in vivo (i.e., triamcinolone acetonide greater than dexamethasone greater than beta-methasone greater than prednisolone greater than hydrocortisone much greater than progesterone approximately tetrahydrocortisone approximately 0). The effect is seen after a 24-hr preincubation with nanomolar to micromolar concentrations of glucocorticoid. In contrast, release of histamine stimulated by the formyl methionine containing peptide f-met-leu-phe, the calcium ionophore A23187, and the tumor-promoting phorbol diester 12-O-tetradecanoylphorbol-13-acetate was not inhibited by 24-hr incubation with the potent glucocorticoid dexamethasone. Dexamethasone inhibited anti-IgE-induced histamine release without altering its rate, suggesting that the glucocorticoids do not inhibit histamine release by elevating the intracellular level of cAMP. Dexamethasone did not consistently alter either the total or occupied basophil IgE Fc receptor number, and therefore the glucocorticoid effect does not appear to be due to the modulation of cell surface Fc epsilon receptor content. These data indicate that steroid hormones inhibit basophil IgE-dependent activation through a specific glucocorticoid receptor. The mechanism by which they do so appears not to involve an elevation of cAMP or a shedding of cell surface Fc epsilon receptors. Further, because the glucocorticoids did not inhibit release initiated by the PLA2-dependent stimuli f-met-leu-phe, A23187 and TPA, the inactivation of IgE-dependent histamine release by glucocorticoids may not be the result of PLA2 inhibition.     

The mechanism of basophil histamine release induced by antigen and by the calcium ionophore A23187.

The mechasism of human basophil histamine release by the calcium ionophore A23187 has been compared to that induced by the interaction of antigen with cell bound IgE antibody. Ionophore induced histamine release (Ion. H.R.) occurs with the leukocytes of both normal and allergic donors. It is completely calcium dependent; LaCl3 inhibits both Ion. H.R. and antigen induced histamine release (Ag. H.R.) at about 10-minus 7 M. The kinetics of Ion. H.R. suggest that this process has no "desensitization" phase as does Ag. H.R. and the ionophore is fully active on antigen-desensitized cells. Pharmacologic studies indicate that dibutyryl cyclic AMP and agents which increase endogenous cyclic AMP levels do not inhibit Ion. H.R. as they inhibit the early stages of Ag. H.R. Of the agents which affect microtubules, colchicine inhibits and D2O enhances Ion. H.R. in a manner which is qualitatively similar but quantitatively less marked than their effects on Ag. H.R. The metabolic antagonist 2-deoxyglucose inhibits both Ion. H.R. and Ag. H.R. in a similar fashion. Based on these data and the observation that cells pretreated with ionophore show a marked (synergistic) enhancement of Ag. H.R. we conclude that Ion. H.R. has a similar or identical mechanism to the later stages if Ag. H.R. but "short circuits" the cyclic AMP-associated events of Ag. H.R.     

Anti-human IgG causes basophil histamine release by acting on IgG-IgE complexes bound to IgE receptors.

We have reexamined the ability of anti-human IgG antibodies to induce histamine release from human basophils. A panel of purified murine mAbs with International Union of Immunological Societies-documented specificity for each of the four subclasses of human IgG was used. Of the 24 allergic subjects studied, the basophils of 75% (18/24) released greater than 10% histamine to one or more anti-IgG1-4 mAb, whereas none of the 13 nonatopic donor's basophils released histamine after stimulation with optimal amounts of anti-IgG mAb. The basophils of 85% (11/13) of the nonatopic donors did respond to anti-IgE challenge, as did 92% (22/24) of the atopic donor cells. Histamine release was induced most frequently by anti-IgG3, and 10/18 anti-IgG responder cells released histamine with mAb specific for two or more different subclass specificities. The rank order for induction of histamine release was anti-IgG3 greater than anti-IgG2 greater than IgG1 greater than anti-IgG4. As in our previous study using polyclonal anti-IgG, 100- to 300-micrograms/ml quantities of the anti-IgG mAb were required for maximal histamine release, about 1000-fold higher than those for comparable release with anti-human IgE. Specificity studies using both immunoassays and inhibition studies with IgE myeloma protein indicated that anti-IgG induced histamine release was not caused by cross-reactivity with IgE. Ig receptors were opened by lactic acid treatment so that the cells could be passively sensitized. Neither IgE myeloma nor IgG myeloma (up to 15 mg/ml) proteins could restore the response to anti-IgG mAb. However, sera from individuals with leukocytes that released histamine upon challenge with anti-IgG mAb could passively sensitize acid-treated leukocytes from both anti-IgG responder and nonresponder donors for an anti-IgG response. The only anti-IgG mAb that induced release from these passively sensitized cells were those to which the serum donor was responsive. Sera from non-IgG responders could not restore an anti-IgG response. These data led to the hypothesis that the IgG specific mAb were binding to IgG-IgE complexes that were attached to the basophil through IgE bound to the IgE receptor. This was shown to be correct because passive sensitization to anti-IgG could be blocked by previous exposure of the basophils to IgE. We conclude that anti-IgG-induced release occurs as a result of binding to IgG anti-IgE antibodies and cross-linking of the IgE receptors on basophils.     

Characteristics of human basophil sulfidopeptide leukotriene release: releasability defined as the ability of the basophil to respond to dimeric cross-links

Human basophils release approximately 90 pmol of LTC4/micrograms histamine when challenged with anti-IgE antibody, but donor to donor variation produces a 1000-fold range of response. There is little conversion to LTC4 to LTE4 in purified preparations of basophils, but conversion to LTE4 does occur if cell densities are high during incubation. Like histamine release, leukotriene release is calcium and temperature dependent and is complete in 20 min, with a t1/2 of approximately 8 min. The process of desensitization also ablates leukotriene release, but there is a distinct two phase process where leukotriene release is enhanced after 5 min of desensitization, whereas histamine release is inhibited and total ablation of leukotriene release occurs only after 45 min of desensitization. Human basophils respond well to stimulation with covalently cross-linked trimeric IgE myeloma but respond poorly to dimeric IgE. This differential sensitivity to the two forms of cross-linked IgE is most exaggerated in the context of leukotriene release, where dimer is 30-fold less efficacious and 100- to 1000-fold less potent than trimer on some donors' basophils. This dichotomy of response is also observed in antigen-challenged cells, where the bivalent hapten, BPO2, also poorly induces leukotriene release in accord with the fact that it predominantly induces dimeric cross-links of penicillin-specific IgE. Anti-IgE dose-response curves reveal a region of dimeric cross-link dominance that may explain the peculiar differences observed in pharmacologic studies of basophil release induced with antigen vs anti-IgE. In addition, there is a continuum of "releasability," where some donors' basophils display no response (histamine or leukotriene release) to dimeric IgE, and others' basophils are essentially equally responsive to both dimeric and trimeric IgE. This releasability difference manifests itself by conferring increased sensitivity to antigenic challenge in those donors' basophils capable of responding to dimeric cross-links such that these donors' basophils are capable of releasing histamine upon antigen challenge while possessing only 50 molecules of cell surface antigen-specific IgE; other dimer-insensitive donors' basophils require 6 to 10-fold greater IgE densities for equal histamine release.     

SG-HQ2 inhibits mast cell-mediated allergic inflammation through suppression of histamine release and pro-inflammatory cytokines

In this study, we investigated the effect of 3,4,5-trihydroxy-N-(8-hydroxyquinolin-2-yl)benzamide) (SG-HQ2), a synthetic analogue of gallic acid (3,4,5-trihydroxybenzoic acid), on the mast cell-mediated allergic inflammation and the possible mechanism of action. Mast cells play major roles in immunoglobulin E-mediated allergic responses by the release of histamine, lipid-derived mediators, and pro-inflammatory cytokines. We previously reported the potential effects of gallic acid using allergic inflammation models. For incremental research, we synthesized the SG-HQ2 by the modification of functional groups from gallic acid. SG-HQ2 attenuated histamine release by the reduction of intracellular calcium in human mast cells and primary peritoneal mast cells. The inhibitory efficacy of SG-HQ2 was similar with gallic acid. Enhanced expression of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β, interleukin-4, and interleukin-6 in activated mast cells was significantly diminished by SG-HQ2 100 times lower concentration of gallic acid. This inhibitory effect was mediated by the reduction of nuclear factor-κB. In animal models, SG-HQ2 inhibited compound 48/80-induced serum histamine release and immunoglobulin E-mediated local allergic reaction, passive cutaneous anaphylaxis. Our results indicate that SG-HQ2, an analogue of gallic acid, might be a possible therapeutic candidate for mast cell-mediated allergic inflammatory diseases through suppression of histamine release and pro-inflammatory cytokines.     

Identification of a receptor for IgG on human granulocytes

The presence of vitamin K-dependent carboxylase was investigated in the microsomal fraction of 20 different types of bovine tissue. Except for muscle, veins, lymphocytes and bone membrane, carboxylase was found in all these preparations, albeit in varying amounts. No differences could be detected between these carboxylating systems with respect to their affinity for vitamin K and warfarin. Most of the endogenous substrates had some affinity towards antiprothrombin or antifactor X.