Complexity of lectin-mediated reactions in bacteria-induced histamine release.

We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations.