Lipopolysaccharide (LPS)-monocyte/macrophage interactions are central to the infected host's inflammatory response to gram-negative bacteria. Flow cytometry was used to analyze the regulation by LPS-specific monoclonal antibodies (MAbs) of fluorescein isothiocyanate-conjugated LPS uptake by human peripheral blood monocytes. The uptake of LPS was stimulated by fresh or heat-inactivated serum (NHS or delta NHS) or by LPS-binding protein and inhibited by alpha-LPS or alpha-CD14 (LPS receptor) MAbs. The inhibition of alpha-LPS uptake was offset in the presence of NHS by a simultaneous MAb-mediated increase in LPS uptake that was blocked by alpha-complement receptor 1. Monocyte tumor necrosis factor-alpha responses to LPS were augmented by NHS and delta NHS and inhibited by alpha-LPS MAbs. Thus, alpha-LPS MAbs down-regulate the proinflammatory uptake of LPS by human monocytes via membrane-bound CD14 while promoting complement-mediated opsonic uptake through membrane-associated CR1.
HeLa cells undergo apoptosis after exposure to cisplatin. Since mitochondria have recently been proposed as a probable effector of this type of cell death, we performed an analysis using the fluorescent cation rhodamine 123, which is transported actively by this organelle. Cisplatin induces a decrease in the mitochondrial staining, as assessed by cytofluorometric analysis. Microscopic analysis demonstrated that this effect was accompanied by damage of the mitochondria. These features were not exclusive of cisplatin, as other antineoplasic agents (taxol, etoposide) elicited similar effects. These results point toward the notion of a general effect of antineoplasic drugs over the mitochondria during induction of apoptotic cell death.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.