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Online Journal of Veterinary Research


 Volume 22 (5):409-416, 2018.

Humoral and cellular immune responses in lambs vaccinated with killed E. Coli O157:H7 vaccines.


1Ali Hussein Fadhil, 2Afaf Abdulrahman Yousif.


1Department(s). of Internal and Preventive Veterinary Medicine, College(s) of Veterinary Medicine, University of Karbala, 2University of Baghdad, Iraq. Corresponding Author : Afaf Abdulrahman Yousif. E. mail: afaf_a.rahman@yahoo.com




Fadhil AH, Yousif AA., Humoral and cellular immune responses in lambs vaccinated with killed E. Coli O157:H7 vaccines,. Onl J Vet Res., 22 (5):409-416, 2018. We report humoral and cellular immune responses of lambs immunized by heat-killed E. coli O157:H7 vaccines with 1X108 or 1X1010CFU/ml. Three groups of 5 Arabi breed lambs each were injected subcutaneously (SC) with 2 ml of killed E coli O157:H7 vaccine with 1X108 CFU/ml mixed with equal volume of adjuvant at 2 week intervals, once with 1X1010 CFU/ml SC with adjuvant, and 2 ml sterile PBS mixed with equal volume of adjuvant twice (PBS controls). Another group of 5 were untreated controls. After vaccinations, lambs were monitored daily for clinical signs and a skin test was done at 21 days. Serum was taken 0, 7, 14, 21, 28, 42, 56, and 70 days for IgG determined by ELISA test. Lambs vaccinated with 11010 CUF /ml showed significant (p ≤ 0.05) increases in skin thickness compare with other groups by 48 hours. Mean serum IgG levels in vaccinated lambs increased significantly at (p ≤ 0.05) at day 7 and 14 after the first injection of vaccine and at days 28 and 42 post after a second booster injection. Serum IgG in controls remained unchanged until day 42. The findings suggest that killed 1X1010 CFU/ml E. coli O157 vaccine could protect sheep against effects of pathogenic E coli.


Key words: ELISA test, immunization, lambs, E. coli O157:H7.