[An attempt to block histamine release from basophils granulocytes with antibodies obtained as a result of long-term immunization].

UNLABELLED

Pathogenetic mechanisms responsible for efficacy of specific immunotherapy still remain to be fully explained. This concerns both desensitization with classic allergens and very rarely used specific immunotherapy with bacteria. Microbes can play important role as hypersensitivity factor in some allergo-inflammatory processes. Bacterial products may act as basophil histamine liberators through immunological (IgE-mediated) and nonimmunological--particular lectin-sugar way. The aim of study was to verify if histamine release triggered by microbes could be modified (blocked) with specific antibacterial antibodies--taking into consideration both of mechanisms of basophil degranulation. The size of immediate (in healthy persons--Tab. 3, 4) and late as well as delayed (in asthmatic patients--Tab. 8) skin reactivity to examined microorganisms and the degree of basophil histamine release induced with these bacteria were compared. Human basophils were isolated from peripheral blood on Ficoll-Hypaque gradient, next challenged with whole, formalin-killed bacteria and with the same bacteria after incubation with specific and nonspecific sera. To differentiate between IgE-dependent and non-immunological mechanisms of histamine release, the IgE molecules were removed from the surface of the basophils by exposure to pH 3.6 (stripping). In each experiment histamine release induced by anti-IgE antibodies was used as control of stripping (Tab. 5, 9). Levels of histamine from the basophils (without and after stripping) incubated with non-coated and specific antibodies coated bacteria were compared. The results were expressed as a percentage of total histamine content in the sample. Histamine release was assayed spectrofluorometrically by using Shore method in Norn modification. The main investigations concerned the basophils from 12 healthy, non-atopic individuals, who had positive immediate skin reactions with at least 1 from 3 microbial strains: Staphylococcus aureus 9615 (unencapsulated), Staphylococcus aureus Smith (encapsulated) and Escherichia coli. Sera containing specific antibodies for these microorganisms were obtained from immunized rabbits. As negative control served sera collected from animals after immunization. Additionally the basophils of 6 asthmatic (intrinsic asthma) patients treated with autovaccines were examined. All patients demonstrated positive late and delayed skin reactions, 3 of them also immediate, to autologous Neisseria and Moraxella species cultured from upper respiratory tract. The bacteria were used as a component of autovaccine and as a basophils stimulating factor in histamine assay. Microbes were incubated with patients own sera before (unspecific serum) and after treatment (source of "specific" antibodies).

CONCLUSIONS

1. Bacteria induced basophil histamine release through two ways: immunological (IgE-mediated) and non-immunological (sugar-lectin interactions). 2. Non-immunological interactions played the main role in basophil histamine release induced by bacteria--both in normal individuals and asthmatic patients. 3. Sera of immunized with bacteria animals partially reduced basophil histamine release induced by homologous strains (Tab. 7). 4. An incubation of autologous bacterial strains with asthmatic patients's sera collected after autovaccines treatment has no influence on basophil histamine release induced by these microbes (Tab. 9). 5. There was no correlation between the skin reactivity to bacteria (both in healthy persons and in asthmatic patients) and the intensity of basophil histamine release induced by microbes.