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.
Ponniah
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Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
Abraham
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Endres
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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