title: Lipopolysaccharide and lipid A-induced human blood lymphocyte activation as detected by a protein A plaque assay.
abstract: Various purified cell wall lipopolysaccharides (LPS) from gram-negative bacteria and derivatives of these LPS were tested for their stimulatory capacity for human peripheral blood cells. Immunoglobulin (Ig) production was tested by an indirect plaque-forming cell assay using Staphylococcus aureus protein A-coupled erythrocytes and specific anti-Ig as developing serum. This method allows the detection of the majority of cells secreting Ig of a single class, and the number of plaque-forming cells detected are approximately 100-1000 times the amount obtained using normal sheep red cells as targets. LPS containing the O antigen-specific chain, as well as mutant products only containing lipid A and ketodeoxyoctonate trisaccharide, could induce cell division and antibody synthesis. The polypeptide antibiotic polymyxin B was found to inhibit LPS-induced activation. Furthermore, purified lipid A, complexed with bovine serum albumin, was also found to activate human peripheral blood B cells. These findings demonstrate that human peripheral blood lymphocytes can be activated by LPS and also indicate that lipid A is the active part of these molecules.
mesh_terms: D004247:DNA / Q000096:biosynthesis; D004306:Dose-Response Relationship, Immunologic; D006462:Hemolytic Plaque Technique; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D008050:Lipid A / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation; D013205:Staphylococcal Protein A / Q000494:pharmacology*
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008050:Lipid A; D008070:Lipopolysaccharides; D013205:Staphylococcal Protein A; D004247:DNA