IMMUNOGENICITY OF VACCINE AGAINST ENZOOTI C ABORTION OF EWES

Immunogenicity of vaccine against enzootic abortion of ewes (EPO) was evaluated in sheep and laboratory white mice. The vaccine contained pu rified and formalin-inactivated corpuscules of Chlamydia psittaci. Exp eriment was performed on ten sheep, Slovak Merino breed, which were ne gative before vaccination in serological assays and blastic transforma tion of lymphocytes (BTL) tests. The animals were immunized subcutaneo usly with 2 ml of vaccine which contained 100 mug (sheep No. 1-4) and 20 mug (sheep No. 5-8) corpuscules of C. psittaci. Control group (No. 9-10) received the same volume of physiological saline. The second dos e of vaccine was given one month after the first dose (No. 1-2 - 100 m ug each, and No. 5-6 - 20 mug each). Blood for serological evaluation and BTL test was taken before vaccination and 1, 3, and 6 months after vaccination. The sheep which were given the second dose of vaccine we re also evaluated two weeks thereafter. Antibody response in complemen t fixation reaction (CFR) and enzyme-linked immunosorbent assay (ELISA ) was compared with the results of BTL. While the antibody response ev aluated by CFR was sporadically positive after administration of the h igher dose of vaccine only, in ELISA all sera were positive except one lower dose of vaccine (Tab. I). In all post-vaccination intervals pos itivity was confirmed by BTL test irrespective of the size and number of vaccine dose (Tab. II). Immunization of mice with one dose (100 mug ) of vaccine significantly but not completely reduced multiplication o f C. psittaci in the lungs of mice (Tab. III).