Participation of CD14 in the Phagocytosis of Smooth‐Type Salmonella typhimurium by the Macrophage‐Like Cell Line, J774.1

Abstract

The role of CD14 in the phagocytosis and killing of microorganisms was investigated using macrophage‐like cell lines, CD14‐positive J774.1 cells and CD14‐negative mutant J7.DEF3 cells derived from J744.1 cells. The cells were infected with Salmonella typhimurium organisms of the smooth (S)‐form LT2, mutant rough (R)‐form TV148 or Staphylococcus aureus 248βH. At 30 or 180 min incubation, the cells were washed and disrupted. Colony‐forming units (CFUs) liberated from the disrupted cells were determined by quantitative cultivation, and the phagocytic index and killing rate were calculated. Both the phagocytic index and killing rate of J774.1 cells against LT2 organisms were greater than those of J7.DEF.3 cells. However, the index and rate of J774.1 cells against TV148 and 248βH organisms were similar to those of the J7.DEF.3 cells. The phagocytosis of LT2 organisms by J774.1 cells was partially inhibited by S‐form LPS (S‐LPS) and anti‐CD14 antibody, but not by R‐chemotype LPS (R‐LPS). These results suggest that CD14 participates in the phagocytosis of S‐form Salmonella.

Inflammatory Responses Induced by the Filarial Nematode Brugia malayi Are Mediated by Lipopolysaccharide-like Activity from Endosymbiotic Wolbachia Bacteria

“…Next we tested whether the presence of the LPS receptor, CD14, was required for the induction of inflammatory responses. Using the cell line J7.DEF.3, which has been se-lected from a parent J774.1 macrophage cell line to be free of surface CD14 (14,15), we show that at low concentrations of parasite extract and LPS, CD14 is required for TNF-␣ responses (Fig. 2).…”

“…Cells were maintained in RPMI 1640 containing 5% FCS, 1% penicillin/streptomycin, 1% genta-mycin, 1% l -glutamine, and 1% nonessential amino acids at 37 Њ C in 5% CO 2 . The macrophage cell line J774.1 and the mutant J7.DEF.3 (14), which does not express membrane CD14 (15), were cultured under similar conditions at a concentration of 1 ϫ 10 5 cells/well. Cells were stimulated with optimal concentrations (1 g/ml) or serial dilutions of Escherichia coli LPS (026:B6; Sigma Chemical Co.) and 50 U/ml IFN-␥ (Genzyme), either singly or in combination, and soluble extracts from filarial parasites for 24 h. Culture supernatants were collected for analysis of cytokines and nitrite.…”

The diacylated lipopeptide FSL-1 enhances phagocytosis of bacteria by macrophages through a Toll-like receptor 2-mediated signalling pathway

“…In order to determine this latter proposal, CHO cells stably expressing TLR2 were established and examined for phagocytosis of these bacteria. For comparative studies, CHO cells stably expressing CD14 (CHO/CD14), which is known to be a phagocytic receptor (Onozuka et al, 1997;Schiff et al, 1997;Devitt et al, 1998;Underhill & Ozinsky, 2002), were also used. However, CHO/ TLR2 cells as well as wild-type CHO-K1 cells failed to take up these bacteria (Fig.…”

Two Distinct Receptors Mediate Nonopsonic Phagocytosis of Different Strains ofPseudomonas aeruginosa

“…CD14 can bind lipopolysaccharide (LPS) molecules [28,29], and binding is facilitated by LPS-binding protein (LBP) [30], which shares homology with lipid transfer proteins [31,32]. By virtue of its ability to bind LPS, CD14 has been implicated in phagocytosis of bacteria, including Escherichia coli [33], M. tuberculosis [34], and Salmonella typhimurium [35]. CD14 also promotes cytokine release after stimulation by a variety of ligands: lipoarabinamannan from M. tuberculosis [34], manuronic acid polymers from P. aeruginosa [36], soluble peptidoglycan fragments from Staphylococcus aureus [37], rhamnose-glucose polymers from Streptococcus mutans [38], and insoluble cell walls from several gram-positive species [39].…”