IFN-gamma as an indicator of successful immunization of goats vaccinated with a killed Cowdria ruminantium vaccine.
Cowdria ruminantium-induced production of IFN-gamma was measured by ELISA on a weekly basis during the course of vaccination with killed organisms emulsified in ISA50. Upon challenge, all (3/3) vaccinated animals that gave the lowest IFN-gamma response died of peracute cowdriosis. On the other hand, only one of three animals showing high IFN-gamma responses to vaccination died, but with a delay of 4 days in comparison with naïve controls. Thus, there seems to be a threshold level of IFN-gamma below which the probability for vaccinated animals to survive a lethal challenge is very low. During challenge, a much lower, but still physiologically meaningful production of IFN-gamma was detected using the 24-hour whole blood assay on day 5 after infection in animals controlling the infection. In contrast, IFN-gamma production was absent or negligible in naïve and vaccinated animals that died within 8-10 days after infection. Although these results need to be validated on a larger number of animals, they strongly suggest that IFN-gamma is a useful indicator of protective immunity in animals immunized with killed COWDRIA:
Esteves
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I
CIRAD-EMVT, Petit-Bourg, Guadeloupe, France (French West Indies). tourais.esteves@cirad.fr
Bensaid
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A
Martinez
D
D
Totte
P
P
D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D002417:Cattle; D004306:Dose-Response Relationship, Immunologic; D016995:Ehrlichia ruminantium / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D015511:Goat Diseases / Q000382:microbiology / Q000517:prevention & control*; D006041:Goats; D006357:Heartwater Disease / Q000382:microbiology / Q000517:prevention & control*; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000097:blood; D007700:Kinetics; D011897:Random Allocation; D015164:Vaccines, Inactivated / Q000276:immunology
D001428:Bacterial Vaccines; D015164:Vaccines, Inactivated; D007371:Interferon-gamma