Abstract
Human uroepithelial (T24) cells were incubated for 24 h in the presence of various concentrations of human recombinant gamma interferon (Hu-rIFN-γ) and then infected with the 6BC strain of Chlamydia psittaci. This resulted in a reduction of intracellular chlamydial inclusion development in proportion to the concentration of Hu-rIFN-γ present when Giemsa-stained cells were examined by light microscopy 24 h after infection. When tryptophan was added to Hu-rIFN-γ-treated cells just after infection, reversal of the Hu-rIFN-γ-mediated inhibition occurred in proportion to the concentration of tryptophan added. Addition of either isoleucine or lysine did not result in reversal of the antichlamydial state. Transport of L-[3H]tryptophan into acid-soluble intracellular pools was found to be greatly enhanced in Hu-rIFN-γ-treated T24 cells compared with the rates measured for untreated cells. Transport of [3H]leucine was not increased in treated cells. Cells treated with Hu-rIFN-γ also degraded L-[3H]tryptophan to catabolites that cochromatographed with N-formylkynurenine and kynurenine as measured by high-performance liquid chromatography. We conclude that Hu-rIFN-γ-mediated inhibition of intracellular C. psittaci replication in T24 cells occurs by depletion of the essential amino acid tryptophan, most likely via the induction of indoleamine-2,3-dioxygenase, the initial enzyme of tryptophan catabolism.
Original language | English (US) |
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Pages (from-to) | 347-351 |
Number of pages | 5 |
Journal | Infection and Immunity |
Volume | 53 |
Issue number | 2 |
DOIs | |
State | Published - 1986 |
Externally published | Yes |
ASJC Scopus subject areas
- Parasitology
- Microbiology
- Immunology
- Infectious Diseases