Lipid A Induces cells, Uniquely Present in Bone Marrow, to Secrete Proteins other than Immunoglobulins

Publisher Website
Google Scholar
Abstract
The [Salmonella spp. and Escherichia coli] lipid-A moiety of lipopolysaccharide induced freshly isolated [rabbit and mouse] bone marrow cells incubated with radioactive leucine to exhibit enhanced release of proteins other than immunoglobulins. Such stimulation by lipopolysaccharide was essentially not observed with cell suspensions from spleen, thymus, appendix, peritoneal exudate, whole blood, lymph node, liver, testis, buffy coat of blood and reticulocyte-enriched blood. The extracellular appearance of proteins was due to secretion by excluding other alternatives. Thus, the rate of cell death and/or leakage of cellular contents, as well as the rate of shedding of surface membrane protein, was unaffected measurably by lipopolysaccharide. Secretion of nonimmunoglobulin proteins was selective, as judged by the finding that the rate of immunoglobulin released by bone marrow cells during the usual 4-h pulse-label period was not stimulated by lipopolysaccharide. Enhancement of mitogenesis and enhancement of secretion of nonimmunoglobulin protein by lipopolysaccharide appeared to occur at independent sites or even in different cells because splenocytes which readily exhibited mitogenic response to lipopolysaccharide essentially did not exhibit stimulation of secretion of nonimmunoglobulin protein.