Mitogenicity of a lipid-deficient lipoprotein from a mutant Escherichia coli strain.
From the mutant bacterial strain Escherichia coli JE5511 lpp lpm, muropeptide-containing and muropeptide-free lipoproteins were prepared. By gas chromatography and by infrared spectroscopy we showed that the products were deficient in the two ester-bound N-terminal fatty acids, but still carried the amide-linked fatty acid. Mutant lipoproteins were tested for mitogenicity in lipopolysaccharide nonresponder C3H/HeJ mice by  incorporation of [3H]thymidine and [3H]uridine and by hemolytic plaque assays for immunoglobulin-secreting plasma cells. Our results showed that the mutant lipoproteins still exhibited marked mitogenicity toward mouse B-lymphocytes, although the activity of the products was reduced in comparison to the wild-type lipoprotein. Thus, the presence of one fatty acid in the N-terminal part of lipoprotein is sufficient to bring about mitogenicity.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis / Q000276:immunology*; D004926:Escherichia coli / Q000032:analysis*; D008074:Lipoproteins / Q000032:analysis / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008934:Mitogens; D009154:Mutation
D001426:Bacterial Proteins; D008074:Lipoproteins; D008934:Mitogens