Insect allergy: the state of the art.
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Biomedical subjects
Publications and source records attributed to L M Lichtenstein.
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The potency of the calcium ionophore A23187 in inducing three activities of human leukocytes (histamine secretion from basophils, enzyme secretion from PMNs, and proliferation of lymphocytes) was markedly dependent on the solvent (DMSO versus ethanol versus aqueous buffer) used for its initial sonication. While 0.1 micrograms/ml of DMSO- and ethanol-solubilized A23187 induced maximal histamine release from basophils and histaminase release from PMNs, concentrations of aqueous buffer-sonicated ionophore of greater than or equal to 1 microgram/ml were required for an equivalent response. Ionophore sonicated in organic solvents caused a maximum release of 40% of PMN beta-glucuronidase, at an optimal concentration tenfold higher than that required for maximal histaminase release; ionophore sonicated in aqueous buffers, even at high concentrations, effected a release of less than 5% of cellular beta-glucuronidase. A23187 also induced lymphocyte proliferation over a narrow concentration range; 0.05 micrograms/l of DMSO-sonicated ionophore induced optimal proliferation and concentrations greater than or equal to 0.2 micrograms/ml were toxic. Twofold higher concentrations of ethanol-sonicated ionophore and fourfold higher concentrations of aqueous-sonicated ionophore were necessary for maximal proliferation, and the magnitude of the maximal response with aqueous-sonicated A23187 was only one-half that of DMSO-solubilized agent. Ionophore-induced release of histamine from basophils and enzymes from PMNs was not cytotoxic, since ionophore induced neither LDH nor histamine release from heat-treated (47 degrees C) cells. These results explain several previous, discordant reports on the presence or absence of an effect of A23187 on cellular secretory events, on differing dose-response relationships, and on cytotoxic versus noncytotoxic mechanisms of action.
Possible functional heterogeneity of human IgE antibody was studied by passively sensitizing human basophils for antigen-induced histamine release. Six sera of known IgE anti-ragweed antigen E and total IgE content were diluted to contain 10 ng of antibody but differed with respect to the ratio of specific/total IgE. The relative ability of the sera to passively sensitize generally reflected the specific/total IgE ratio but one serum was 2.5 times more active than the remainder. This ability did not reflect the IgG antibody level nor was it due to a dialyzable or heat-stable factor. These data indicate functional IgE heterogeneity, probably due to the interaction of the Fc portion of IgE with the basophil receptor.
These studies describe the IgE-mediated relase of a basophil kallikrein-like enzyme that is an arginine esterase and is inhibited by plasma, diisopropylphosphofluoridate, and Trasylol. The substrate specificity for the synthetic amino acid ester substrates p-toluenesulfonyl-L-arginien methyl ester, benzoyl-arginine methyl ester, and acetyl-tyrosine methyl ester is similar for the basophil enzyme and plasma kallikrein. The interaction of arginine esterase-active fractions from ion-exchange (DEAE-Sephacel) and gel filtration (Sepharose 6B) chromatography, with human plasma kininogen, generates immunoreactive kinin. The basophil arginine esterase and kinin-generating activities co-chromatograph on Sepharose 6B and the quantity of kinin generated is, in general, proportional to the arginine esterase activity of the column fractions, suggesting that these two activities are subserved by the same protease. The ability of this protease to generate kinin equally well from heat- and acid-treated plasma, as from fresh human plasma, suggests that this protease has kallikrein-like activity. These data suggest that kallikrein-like activity can be generated from human basophils as a direct result of a primary IgE-mediated immune reaction, thus providing a potential link between reactions of immediate hypersensitivity and the plasma and(or) tissue kinin-generating systems.
This report describes the immune release of a new mediator from human peripheral leukocytes, a basophil kallikrein-like activity (BK-A). The release process is initiated by the interaction of antigen on anti-IgE with cell-bound IgE, and appears to be similar in mechanism to the relase of histamine and other mediators of the immediate hypersensitivity reaction. The dose-response relationships and kinetics of histamine and BK-A release from antigen-challenged peripheral leukocytes are similar. The relase of the BK-A is calcium and temperature dependent, requires metabolic energy, and is controlled by hormone-receptor interactions that influence the cellular level of cyclic AMP, as has been described for other mediators of immediate hypersensitivity reactions. The data indicate that the interaction of BK-A with human plasma kininogen, generates immunoreactive kinin. We conclude that the antigen-IgE interation leads to the release from human basophils of a new mediator, a basophil kallikrein-like activity which may well be a link between reactions of immediate hypersenstivitity and the plasma and/or tissue kinin-generating systems.
Purified human C3a and synthetic COOH-terminal peptides of C3a, i.e., a pentapeptide, Leu-Gly-Leu-Ala-Arg (5R), and an octapeptide, Ala-Ala-Ala-Leu-Gly-Leu-Ala-Arg (8R) induced histamine release from human basophil granulocytes. On a molar basis, 5R was one-tenth and 8R was one-fifth as active as C3a in causing histamine release. It was found that 125I-C3a binds to whole leukocytes, interacting with both mononuclear cells and neutrophils and the binding was inhibited by preincubation of cells with unlabeled C3a, but not by C5a. 5R and 8R also inhibited the binding of 125I-C3a to the cells. However, on a molar basis, 2,000 times more 8R or 6,000 times more 5R is required for 50% inhibition of 125I-C3a binding as compared with native C3a. Autoradiography of cells using 125I-C3a and 125I-C5a showed preferential binding of 125I-C3a to eosinophils and basophils, whereas 125I-C5a binds primarily to neutrophils and eosinophils and to a lesser extent to basophils. The preferential binding of C3a and C5a to different cell types may herald significance related to their physiological functions.
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We earlier reported the IgE-mediated release of a basophil kallikrein of anaphylaxis (BK-A) which, like plasma kallikrein, is an arginine esterase and cleaves human plasma kininogen generating immunoreactive kinin. We herein report that, like plasma kallikrein, preparations rich in this basophil protease also activate human Hageman Factor by proteolytic cleavage of the zymogen molecule into light and heavy chains. These fragments of 28,000 and 52,000 daltons are similar in size to those produced during activation of Hageman Factor by plasma kallikrein. Exposure of Hageman Factor (bound to a negatively charged surface) to BK-A led to the proteolytic cleavage of Hageman Factor producing a 28,000 molecular weight fragment (HFa) which is functionally active and capable of activating prekallikrein to kallikrein. We conclude that, during anaphylaxis, basophils may release a protease that is capable of cleaving and activating Hageman Factor, thus providing a mechanism for initiating the in vivo activation of the Hageman Factor dependent systems.
These studies describe the IgE-mediated release of a basophil kallikrein of anaphylaxis (BK-A) that has arginine esterase activity and is inhibited by plasma, DFP, and Trasylol. The interaction of BK-A active fractions from ion exchange (DEAE-Sephacel) and gel filtration (Sepharose 6B) chromatography, with human plasma kininogen generates immunoreactive kinin. The BK-A and kinin-generating activities co-chromatograph on DEAE-Sephacel and Sepharose 6B columns, and the quantity of kinin generated is, in general, proportional to the BK-A activity of the column fractions, suggesting that these two activities are subserved by the same protease. These data suggest that kallikrein-like activity can be generated from human basophils as a direct result of a primary IgE-mediated immune reaction, thus providing a potential link between reactions of immediate hypersensitivity and the plasma and/or tissue kinin-generating systems.
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Strontium will substitute for calcium in the activation of histamine secretion from human basophil leukocytes stimulated by an immunologic reaction or by the ionophore A23187. Strontium is required in 10-fold higher concentration (1 to 10 mM) to activate histamine release compared with calcium (0.1 to 1.0 mM). In terms of maximum release obtainable for a particular immunologic stimulus, strontium is more effective than calcium. Results are presented to show that calcium and strontium act at the same site but strontium is a more sensitive probe for that site. Strontium can be used to demonstrate that immunologic stimuli activate calcium-binding sites in basophils even when no secretion is observed in the presence of calcium. It is suggested that the degree of secretion observed from basophils depends on the number of occupied Fc receptors for IgE and the coupling of these Fc receptors to calcium transport sites.
Basophil leukocytes from human blood secrete histamine in the absence of a membrane stimulus when incubated in a medium containing Sr++, 1 to 10 mM. Spontaneous histamine secretion in the presence of Sr++ is inhibited by La+++, 1 to 1000 nM and 2 deoxy-D-glucose, 30 to 300 microM. Spontaneous secretion in the presence of Sr++ increases with increasing pH in the range 6.5 to 8.5. Agents which cause a rise of intracellular cyclic AMP level increase the spontaneous secretion in 194th presence of Sr++. The results suggest that spontaneous histamine release is a secretory response of the cells, and evidence is provided for a dual role of cyclic AMP in the control of histamine secretion.
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It was observed previously that serum-treated zymosan particles (Zx) augmented antigen and anti-IgE stimulated histamine release. With most of the enhancement attributed to an increased rate of release, this suggested that Zx was active only during the course of IgE-mediated release. This association between IgE-mediated histamine release and responsiveness to Zx was examined further in the present report. Addition of Zx at various time intervals after release had been initiated indicated that the basophil responsiveness to Zx was limited in duration; maximum responsiveness to Zx correlated closely with the period in which the rate of IgE-mediated histamine release was maximum. The time-dependent decline in sensitivity to Zx paralleled the kinetics for desensitization to antigen. Addition of Zx failed to cause release from basophils desensitized in vitro or from basophils of a donor who failed to release histamine upon challenge with anti-IgE. In contrast to the enhancement of IgE-mediated release, Zx did not augment histamine release caused by C5a or the synthetic peptide f-Met-Leu-Phe. It is concluded that an obligatory link exists between ongoing IgE-mediated histamine release and enhancement by Zx.
Adenosine, at physiologic concentrations, inhibits in vitro IgE-mediated human basophil histamine release in a dose-dependent fashion. The inhibition dose-response curve is paralleled by an adenosine-induced increase in cAMP levels of human leukocyte preparations. Further evidence that the adenosine effect is related to changes in cAMP levels is that the nucleoside inhibits only in the first stage of antigen-induced histamine release and fails to inhibit the release caused by ionophore A23187. A poorly metabolized derivative of adenosine, 2-chloroadenosine inhibits as effectively as adenosine; dipyridamole, which blocks adenosine uptake, does not impair the inhibition caused by adenosine. Finally, theophylline, which is a competitive antagonist of adenosine in human lymphocytes also blocks the inhibition of release caused by adenosine. These data suggest that adenosine acts via a specific cell-surface receptor linked to adenylate cyclase. It appears that the human basophil has a specific receptor for adenosine and that this nucleoside may modulate the in vivo release of the mediators of immediate hypersensitivity reactions.