Recombinant ovine interferon gamma inhibits the multiplication of Chlamydia psittaci in ovine cells.
The local production of interferon-gamma (IFN-gamma) in sheep in response to Chlamydia psittaci was measured by cannulation of the efferent lymph duct draining the site of challenge inoculation. Peak production of IFN-gamma (256 U/ml) was detected 24 h after challenge. Based on these physiological data, functional studies were carried out in vitro to determine the effect of recombinant ovine (rOv) IFN-gamma on the multiplication of C. psittaci in ovine fibroblasts. IFN-gamma inhibited the multiplication of C. psittaci in ovine cells over a range of concentrations (250 U/ml to 2.5 U/ml) in a dose-dependent manner. The inhibition of chlamydial multiplication was most pronounced when cells were treated with rOvIFN-gamma for 24 h before infection. The addition of exogenous L-tryptophan (500 micrograms/ml) to cultures within 48th of infection abrogated the anti-chlamydial effect of rOvIFN-gamma thus suggesting that tryptophan deprivation is an anti-chlamydial mechanism induced by rOvIFN-gamma in these ovine cells.
Graham
S P
SP
Moredun Research Institute, Edinburgh, UK.
Jones
G E
GE
MacLean
M
M
Livingstone
M
M
Entrican
G
G
D000818:Animals; D002691:Chlamydophila psittaci / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000382:microbiology; D007371:Interferon-gamma / Q000032:analysis / Q000494:pharmacology*; D008196:Lymph / Q000737:chemistry; D009956:Psittacosis / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D011994:Recombinant Proteins; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000382:microbiology*; D013997:Time Factors; D014364:Tryptophan / Q000494:pharmacology
D011994:Recombinant Proteins; D007371:Interferon-gamma; D014364:Tryptophan