CHEMICAL AND BIOLOGICAL PROPERTIES OF A PROTEIN-RICH FRACTION OF BACTERIAL LIPOPOLYSACCHARIDES .2. INVITRO RAT PERITONEAL MAST-CELL RESPONSE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 119  (5) , 1790-1795
Abstract
Lipid A-associated protein (LAP) isolated from preparations of bacterial lipopolysaccharides (LPS, endotoxins) was demonstrated to initiate the release of amines from rat peritoneal mast cells. The release at low concentrations of LAP requires both cellular energy and Ca and appears to be a true secretory response. At higher concentrations the release is independent of these variables. The time required for maximal response is approximately 10-15 min at 37.degree. C. The response appears to be a general property of Escherichia coli LAP preparations since LAP isolated from 3 serotypes of these organisms all have similar activity. On the basis of heat lability at 100.degree. C, the ability of LAP to initiate mast cell secretion appears to be independent of its ability mitogenically to stimulate murine B [bone marrow derived] lymphocytes.