COMPARATIVE-STUDIES OF CYTOTOXICITY AND THE RELEASE OF TNF-ALPHA, NITRIC-OXIDE, AND EICOSANOIDS OF LIVER MACROPHAGES TREATED WITH LIPOPOLYSACCHARIDE AND LIPOSOME-ENCAPSULATED MTP-PE
P. Dieter et al., COMPARATIVE-STUDIES OF CYTOTOXICITY AND THE RELEASE OF TNF-ALPHA, NITRIC-OXIDE, AND EICOSANOIDS OF LIVER MACROPHAGES TREATED WITH LIPOPOLYSACCHARIDE AND LIPOSOME-ENCAPSULATED MTP-PE, The Journal of immunology, 155(5), 1995, pp. 2595-2604
LPS and liposome-encapsulated MTP-PE induce in liver macrophages cytot
oxicity against tumor target cells and a release of TNF-alpha, nitric
oxide, and eicosanoids but not a generation of superoxide anions. Neit
her agent elicits a formation of inositol phosphates, a change in intr
acellular free calcium, or a translocation of protein kinase C-beta. I
nhibition or down-regulation of protein kinase C does not inhibit the
release of TNF-alpha and nitric oxide but inhibits the formation of pr
ostanoids. In contrast to LPS, liposome-encapsulated MTP-PE induces an
elevation of diacylglycerol mass and an enhanced expression of protei
n kinase C-delta. LPS, but not liposome-encapsulated MTP-PE, elicits a
n enhanced expression of cytosolic phospholipase A(2) and a predominan
t formation of PGE(2). Both agents elicit different responses when giv
en to cells pretreated with one of the immunomodulators, with dexameth
asone, or with PGE(2). In contrast to liposome-encapsulated MTP-PE, LP
S induces only cytotoxicity when added to liver macrophages simultaneo
usly or a maximum of 2 h before the addition of tumor target cells. Th
e observed differences might reflect partly differences in the potenci
es of LPS and liposome-encapsulated MTP-PE as immunomodulators.