T-cell-independent stimulation of immunoglobulin secretion in resting human B lymphocytes by the mannose-specific adhesin of Escherichia coli type 1 fimbriae.
Purified Escherichia coli type 1 fimbriae have been shown previously to stimulate T-cell-independent proliferation of human B lymphocytes. The response is mediated by the mannose-specific, lectin-like adhesin protein FimH. Here we show that type 1 fimbriae also stimulate immunoglobulin (Ig) secretion by B cells. The response was maximal at three days of culture and consisted predominantly of the IgM isotype. It was independent of serum components, T lymphocytes, monocytes, and natural killer cells. Highly purified resting B cells were induced to proliferate and secrete Ig in response to the fimbriae. The role of FimH in the response was shown by the failure of FimH- type 1 fimbriae to stimulate and by inhibition of the response with alpha-methyl mannoside. In light of the fact that carbohydrate-binding adhesins have been found on a wide variety of microorganisms, these studies suggest the possibility that responses of other cell types to other microbial adhesins will be discovered.
Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
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Ponniah
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Abraham
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D018830:Adhesins, Escherichia coli; D001402:B-Lymphocytes / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000494:pharmacology*; D002478:Cells, Cultured; D010861:Fimbriae, Bacterial / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis*; D008358:Mannose / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000502:physiology*
D018830:Adhesins, Escherichia coli; D001425:Bacterial Outer Membrane Proteins; D007136:Immunoglobulins; D008358:Mannose