Development of egg yolk-based polyclonal antibodies and immunoprophylactic potential of antigen-antibody complex against infectious bursal disease

Abstract

A study conducted in the Faisalabad district sampled 50 cases across five IBD outbreaks, revealing an alarming 80 % infection rate among poultry. Our research focused on developing an immune complex (Antigen-antibody complex) with potential immunoprophylactic benefits to counter this formidable threat. Our study was based on producing egg yolk-derived polyclonal antibodies (IgY) targeting IBDV. Commercial layer birds were immunized with inactivated IBDV, yielding IgY antibodies extracted from their eggs exhibited substantially higher and more enduring antibody titers, with a geometric mean titer of 104. Further research involved the creation of an immune complex (ICx) where antigen was extracted from infected bursae tissues. The immunogenic response of ICx was assessed in poultry birds after a challenge with a virulent strain of IBD virus and compared to a conventional IBDV vaccine in poultry. Results revealed significantly higher and more enduring antibody titers induced by the ICx, offering enhanced protective immunity against the IBDV challenge, as evidenced by lower Bursa to bodyweight ratios in vaccinated birds.

Keywords

• Immune complex
• Infectious bursal disease virus
• Immunoglobulin-Y
• Polyclonal antibodies
• Bursa of Fabricius