Preparation of Live Attenuated Corynebacterium pseudotuberculosis Vaccine against Caseous Lymphadenitis in Sheep

Mohamed, Marwah M; El-Sergany, Elham F; Osman, Roukaya M; El Sebaie, Nadine A

doi:10.21608/ejvs.2025.382503.2832

Preparation of Live Attenuated Corynebacterium pseudotuberculosis Vaccine against Caseous Lymphadenitis in Sheep

Document Type : Original Article

Authors

¹ Bacterial Diagnostic Products Department, Veterinary Serum and Vaccine Research Institute (VSVRI), Agriculture Research Center (ARC), Cairo, Egypt.

² Anaerobic Bacterial Vaccine Research Department, Veterinary Serum and Vaccine Research Institute (VSVRI), Agriculture Research Center (ARC), Cairo, Egypt.

³ Genetic Engineering Research Department, Veterinary serum and Vaccines research institute, Cairo, Egypt.

10.21608/ejvs.2025.382503.2832

Abstract

Caseous lymphadenitis (CLA) is a chronic granulomatous disease commonly occur in small ruminants, caused by a gram positive Corynebacterium pseudotuberculosis. The present study aimed to identify the suitable attenuation method for Corynebacterium pseudotuberculosis Ovis and to evaluate the immunogenicity of the resulting live attenuated vaccine in sheep. Various attenuation methods were assessed, including; thermal treatment at 55 °C for 15 minutes, exposure to alkaline pH (pH11) and treatment with crystal violet (1/ 250.000 concentration). These methods resulted in significant alteration in the bacteria cultural and biochemical characteristics, as well as a reduction in its virulence by decreasing the invasive power of the ovine strain. The strain attenuated using crystal violet was selected for vaccine formulation. Ten native sheep were vaccinated with the crystal violet live attenuated C. ovis vaccine, humoral and cellular immune response were assessed. Results demonstrated that, the prepared live attenuated vaccine induce a robust immune response, indicating its potential efficacy. In conclusion, the developed live attenuated C. ovis vaccine is safe and eliciting a strong immune response in sheep which represents a promising strategy for controlling of the CLA infection in sheep with potential to reduce the economic impact of the disease in sheep industry.

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