Ensayo de vacunas inactivadas experimentales contra el aborto enzoótico ovino utilizando ratones resistentes a la infección por chlamydophila abortus

Abstract

Ovine enzootic abortion (OEA), which is caused by Chlamydophila abortus (Chlamydia psittaci, serotype 1) is the main cause of abortion in small rumiants. There are two types of commercially available vaccines for the control of this disease: inactivated vaccines and attenuated vaccine. Inactivated vaccines are avoid abortions in the flock, but some shedding of the microorganism is still detectable during labour. The attenuated vaccine is a live vaccine, so its use implies some danger for the veterinary and stockbreeder, and also may be reactivated in the vaccinated animals. For the present study we used a mouse model C57BL/6Ha (H-2b), experimentally showed to be resistant to the infection with C. abortus. We have designed five experimental inactivated vaccines against OEA associating the inactivated bacteria to different adjutants like Alum Hydroxyl, QS-21, GPI-0100, Montanide ISA773 and Montanide ISA35. The protection conferred by these vaccines has been analysed. In order to determine which was the most effective, we have evaluated several parameters: inoculation site lesions, percentages of weight loss, bacterial recovery from liver, and IFN-g and IgG production in sera at 4 days post-infection. The best protection was shown using the QS-21 and Montanide 773 experimental vaccines.