Mitogenic stimulation of human B lymphocytes by the mannose-specific adhesin on Escherichia coli type 1 fimbriae.
Escherichia coli type 1 fimbriae contain in association with the major structural protein a lectin-like adhesin moiety that mediates attachment of E. coli to mannose-containing receptors on the surface of host cells. We have investigated the lymphocyte mitogenic activity of this mannose-specific adhesin by comparing the ability of purified wild type type 1 fimbriae containing the adhesin and mutant type 1 fimbriae lacking the adhesin to stimulate proliferation in human lymphocytes. Both fimbriae stimulated a peak of proliferation at 8 days whereas only the wild type fimbriae stimulated an additional peak of proliferation occurring at 3 days. Proliferation at 3 days but not at 8 days could be blocked by the addition of alpha-methyl-D-mannoside. Neonatal lymphocytes from umbilical cord blood responded to both wild type and mutant fimbriae in a fashion similar to adult cells. Stimulation of separated T and non-T cell populations indicated that the proliferation seen at 3 days was solely due to non-T cells whereas the 8-day response was due to T cell proliferation. The addition of gamma-irradiated T cells did not appear to enhance the 3-day response of the non-T cells. However, the 8-day response by T cells was dependent on the presence of gamma-irradiated non-T cells. In cultures of unseparated cells, wild type fimbriae stimulated more than 75% of the B cells to enter the S and G2 phase at 3 days whereas at 8 days cycling T cells were present in both wild type and mutant fimbriae-stimulated cultures. Taken together, our observations suggest that the adhesin molecule stimulates a polyclonal mitogenic response in B cells that peaks at 3 days, and other structural components of the fimbriae are responsible for evoking an 8-day (probably immune) response in T cells.
Ponniah
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Department of Medicine, University of Tennessee, Memphis 38163.
Abraham
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Dockter
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Wall
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Endres
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D018830:Adhesins, Escherichia coli; D000328:Adult; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins; D004926:Escherichia coli / Q000276:immunology*; D005312:Fetal Blood; D010861:Fimbriae, Bacterial / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008358:Mannose / Q000502:physiology; D008934:Mitogens; D012397:Rosette Formation
D018830:Adhesins, Escherichia coli; D001425:Bacterial Outer Membrane Proteins; D008934:Mitogens; D008358:Mannose