Introduction:
Minahil Ashraf is a dedicated microbiologist and researcher from the University of Veterinary and Animal Sciences (UVAS), Lahore, where she completed her BS (Hons) in Applied Microbiology and earned her MPhil in Microbiology at the Institute of Microbiology (IOM) under the supervision of Prof. Dr. Aamir Ghafoor. Her research focused on the development and evaluation of a gamma-irradiated inactivated vaccine against fowl typhoid, reflecting her deep interest in immunology, vaccine development, and host-pathogen interactions. For this work, she received the Prof. Dr. Aftab Ahmad Anjum Research Award at the International Poultry Science Conference, and her findings are published in the journal Vaccine. Minahil continues to pursue research dedicated to innovative solutions for improving animal health and disease prevention.
Supervisor: Prof. Dr Aamir Ghafoor
Topic: Development and Evaluation of Protective Efficacy and Safety of Gamma-Irradiated Inactivated Vaccine against Fowl Typhoid
Author(s): Minahil Ashraf¹, Aamir Ghafoor¹, Muhammad Suleman², Masham Mukhtar¹, Muhammad Umer Farooq1, Umar Bin Zahoor1, Muhammad Hassan Mushtaq³
¹ Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore.
² Department of Pathology, University of Veterinary and Animal Sciences, Lahore.
³ Department of Epidemiology and Public Health, University of Veterinary and Animal Sciences, Lahore.
Abstract:
Gamma-irradiated vaccines are emerging as safer alternatives to conventional live attenuated and inactivated vaccines. In this study, gamma-irradiated Salmonella Gallinarum (γ-SG) vaccine was developed from a local field isolate and its immunogenicity was evaluated in broilers. Radiation doses ranging from 1.5-10 kGy were evaluated and 7 kGy was optimized as the effective dose that completely inhibited replication while maintaining residual metabolic activity. For immunization-challenge experiment, broilers at 14 days of age were vaccinated twice at two-week intervals with γ-SG (oral), oil-based γ-SG (IM), oil-based formalin-inactivated SG (F-SG) and commercial SG 9R vaccine. Each vaccine was administered at a concentration of 2 × 108 CFU and SG 9R at 2 × 107 CFU in 0.2 mL PBS. At three weeks post-vaccination γ-SG (Oral) showed the highest CD4+ T cell response (39.74%) compared with SG 9R (29.36%), γ-SG (IM) (20.2%) and F-SG (22.8%). CD8+ T cell response was elevated in γ-SG (Oral) (28.6%) compared with SG 9R (5.28%), γ-SG(IM) (19.7%) and F-SG (14.3%). IFN-γ concentrations were significantly elevated in γ-SG(Oral) (452.75 pg/mL) compared with SG 9R (307.5 pg/mL), γ-SG (IM) (334 pg/mL), and F-SG (221.75 pg/mL). A similar increase was observed in IgG antibody response, with γ-SG (Oral) eliciting the strongest response among the groups. Challenge study demonstrated complete protection with γ-SG (Oral) (100% survival), equivalent to SG 9R, whereas F-SG and γ-SG (IM) conferred partial protection with 40% and 20% mortality respectively, compared with 70% mortality in unvaccinated control. These findings underscore the potential of γ-SG (Oral) as a safe and promising vaccine candidate.
Key Words: Fowl Typhoid, Gamma Irradiated, Inactivated Vaccine, IgG, CD4+T Cells, CD8+T Cells