Suppressed Production of Pro-inflammatory Cytokines by LPS-Activated Macrophages after Treatment with Toxoplasma gondii Lysate

Abstract

During Toxoplasma gondii infection, macrophages, dendritic cells, and neutrophils are important sources of pro-inflammatory cytokines from the host. To counteract the pro-inflammatory activities, T. gondii is known to have several mechanisms inducing down-regulation of the host immunity. In the present study, we analyzed the production of proand anti-inflammatory cytokines from a human myelomonocytic cell line, THP-1 cells, in response to treatment with T. gondii lysate or lipopolysaccharide (LPS). Treatment of THP-1 cells with LPS induced production of IL-12, TNF-α , IL-8, and IL-10. Co-treatment of THP-1 cells with T. gondii lysate inhibited the LPS-induced IL-12, IL-8 and TNF-αexpression, but increased the level of IL-10 synergistically. IL-12 and IL-10 production was down-regulated by anti-human toll-like receptor (TLR)-2 and TLR4 antibodies. T. gondii lysate triggered nuclear factor (NF)-κ B-dependent IL-8 expression in HEK293 cells transfected with TLR2. It is suggested that immunosuppression induced by T. gondii lysate treatment might occur via TLR2-mediated NF-κ B activation.

Secreted Toxoplasma gondii molecules interfere with expression of MHC-II in interferon gamma-activated macrophages

“…Cells treated with the PK-digested lysates showed normal MHC-II levels (only 4% inhibition) comparable with IFNc-treated control cultures, indicating a complete loss of inhibitory activity. These observations strongly suggested that the inhibitory activity was associated with molecules of a proteinaceous nature and correlate with previous reports (Lang et al, 2006;Lee et al, 2008). No adverse effect was observed in control cultures that were treated with the mixture (PK + Pefabloc + protector solution) devoid of any proteins, indicating that the compounds did not affect MHC-II expression in the other samples.…”

Proinflammatory Cytokine and Nitric Oxide Production by Human Macrophages Stimulated with Trichomonas vaginalis

“…After HMDM coincubated with live T. vaginalis for 30 min, mRNA expressions of TNF-αwas measured by RT-PCR [11]. Total RNA was extracted from cells using Trizol reagent (Invitrogen) according to the method described previously [11].…”

“…After HMDM coincubated with live T. vaginalis for 30 min, mRNA expressions of TNF-αwas measured by RT-PCR [11]. Total RNA was extracted from cells using Trizol reagent (Invitrogen) according to the method described previously [11]. Primer sequences and PCR conditions used for amplification of β -actin and TNF-αwere as follows: β -actin (sense) 5′ -CCAGAG-CAAGAGAGGTATCC-3′ , (antisense) 5′ -CTGTGGTGGTGAAGC-TGTAG-3′ ; PCR conditions of initial DNA denaturation at 95℃ for 10 min and 30 rounds of denaturation (95℃ for 45 sec), annealing (58℃ for 2.5 min), and extension (72℃ for 1 min).…”

Suppressed CD31 Expression in Sarcoma-180 Tumors after Injection with Toxoplasma gondii Lysate Antigen in BALB/c Mice

“…All experiments using mice were performed according to the ethical standards formulated from the IACUC (SNU-090102-3) in the Seoul National University. TLA were prepared according to the procedure described previously, with a slight modification [14]. Briefly, tachyzoites of the virulent T. gondii RH strain were obtained from the peritoneal exudate of intraperitoneally-infected mice.…”