Effect of Phage Targeting Therapy of Brucellosis on Host Antibody Response in Cattle.

Brucellosis caused by Brucella organisms is a major zoonosis globally. It causes heavy losses through abortions, delayed conception, and infertility in animals. Brucella is an intracellular bacterium. Antibiotic therapy for bovine Brucellosis is expensive and may sometimes be ineffective as Brucella can become resistant. Once infected, the animal may remain carrier and shed bacteria in milk, semen, and uterine discharges spreading infection to others for a long period. The live attenuated Brucella abortus strain S19 organisms that are commonly used as a vaccine were employed to deliver a broad acting lytic brucellaphage inside the phagocytes in vivo to reach the virulent Brucella hiding intracellularly. The phage pulsed vaccine induced sustained and significantly high titers of anti-Brucella antibodies compared with the untreated animals and animals vaccinated with S19 vaccine alone as estimated by standard tube agglutination test, microagglutination test, indirect hemagglutination assay test, and enzyme-linked immunosorbent assay. The current investigation is perhaps the first systematic attempt whereby efficacy of brucellaphage pulsed vaccine preparation in induction of specific antibody response was evaluated in cattle. Copyright 2020, Mary Ann Liebert, Inc., publishers.