Lipopolysaccharide inhibits the production of lymphocytic choriomeningitis virus in a human monocytic cell line

Abstract

The human monocytic cell line THP-1 was used as a model to study the mechanism of infection in the monocyte/macrophage, a natural target of lymphocytic choriomeningitis virus (LCMV) infection in vivo. Both the virulent strain, LCMV. WE, and the avirulent strain, LCMV. ARM, infected THP-1 cells, but did not stimulate THP-1 cells to secrete interleukin 1 (IL-1) or tumour necrosis factor (TNF-~). When lipopolysaccharide (LPS) was added to THP-1 cells together with LCMV, an 80 to 90 % reduction in the number of infected cells (measured by immunofluorescence) and a 90 % reduction in viral plaques was observed 5 to 6 days postinfection. Neither interferon ~t (IFN-~) nor IFN-fl were detected in supernatants from THP-1 cells after the addition of LCMV, LPS, or LPS plus LCMV. In contrast, the same levels of IL-1 and TNF-~ were observed in the presence of LPS and LCMV, or LPS alone. However, antibodies to IL-1, TNF-ct, intedeukin 6 and IFN-~ did not block the antiviral effect of LPS. In kinetic studies, LPS added 1 day after adding LCMV to THP-1 ceils was still effective in reducing the number of infected cells. Our findings suggest that LPS alters cellular metabolism, possibly through the induction of IFN-~, and that IFN-~ in the absence of LPS suppresses virus production.

Infection of Murine Macrophages by Salmonella enterica Serovar Heidelberg Blocks Murine Norovirus Infectivity and Virus-induced Apoptosis

“…Such observations have been previously reported for Dengue Virus infection of human monocytes/macrophages, where the bacterial lipopolysaccharide (LPS) engages the CD14 receptor and blocks Dengue Virus entry and replication if the LPS is added to cells before Dengue Virus infection, but the virus is able to replicate efficiently if the virus infection precedes LPS exposure [ 43 ]. Similar observations have also been reported for HIV-1 and Lymphocytic Choriomeningitis Virus (LCMV) [ 44 – 46 ]. Further studies are needed to evaluate this hypothesis.…”

Bacterial Lipopolysaccharide Inhibits Dengue Virus Infection of Primary Human Monocytes/Macrophages by Blockade of Virus Entry via a CD14-Dependent Mechanism

“…LPS was known to induce massive MO/M activation and the release of a wide variety of soluble mediators that are responsible for the in vitro antiviral effect of LPS on several viral infections of human MO/M (4,12,(19)(20)38). However, we failed to observe any relationship between DV yields and the levels of secreted cytokines and chemokines in the MO/M cultures (data not shown).…”