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FEMS Immunol Med Microbiol. 1996 Jun;14(2-3):109-20.

Nitric oxide production: a mechanism of Chlamydia trachomatis inhibition in interferon-gamma-treated RAW264.7 cells.

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Department of Microbiology, James Quillen College of Medicine, East Tennessee State University, Johnson City 37614, USA.


IFN-gamma and/or LPS induced nitrite production and inhibition of Chlamydia trachomatis (CT) replication in the murine macrophage cell line, RAW264.7. Linear regression analysis demonstrated a strong correlation between nitrite production and inhibition of CT replication (correlation coefficients: -0.93, P < 0.001). L-NMMA specifically inhibited nitrite production and restored CT replication (55-71%). Inducible nitric oxide synthase (iNOS) mRNA was analyzed by Northern and dot blot hybridization with an iNOS cDNA probe. A strong correlation between iNOS mRNA expression and inhibition of CT replication also was observed (correlation coefficient: -0.97, P < 0.05). Furthermore, anti-TNF-alpha antibody, which completely neutralized biological activity of the secreted TNF-alpha, neither inhibited nitrite production nor restored CT replication in the LPS- and/or IFN-gamma-treated RAW264.7 cells. In mouse peritoneal macrophages treated with IFN-gamma, both L-NMMA and anti-TNF-alpha antibody inhibited nitrite production and restored CT replication. However, L-NMMA and the antibody had no effect upon nitrite production and CT inhibition in LPS-treated peritoneal macrophages. These data indicate that NO production is one mechanism for inhibition of CT replication in IFN-gamma-activated murine macrophages.

[Indexed for MEDLINE]

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