Immunohistochemical determination of viral antigen localizations in chicks vaccinated with infectious bursal disease (Gumboro diseases) virus vaccine

Aydın Z. Aydın Adnan Menderes University Institute of Health Sciences Pathology (Veterinary) Master's Thesis, Aydın, 2024. Objective: This thesis study aims to determine the immunohistochemical distribution of viral antigen and macroscopic and histopathological findings, in chicks vaccinated with Infectious bursal disease attenuated immunocomplex virus (IBDV). Materials and Methods: In the study, histopathological and immunohistochemical findings of 41 chicks vaccinated with IBDV vaccine were examined. The animals were euthanized on the 1st, 3rd, 5th, 10th, 20th, 30th and 40th days, necropsies were performed, the tissue samples taken were fixed in formol solution, dehydrated in alcohols, and blocked in paraffin. Sections of 4 µm thickness were taken with a microtome and stained with hematoxylin and eosin for microscopic examination. The IBDV antibody used in the immunohistochemical examination was obtained from a New Zealand Albino rabbit. For immunohistochemical examination, the avidin-biotin immunoperoxidase method was applied to serial sections. Results: In histopathological examination, edema and necrosis characterized by karyolysis, karyorrhexis and karyopyknosis in lymphocytes were observed in the bursa fabricius, and primary follicle formations related to vaccine stimulation were observed in the spleen tissue. In immunohistochemical examination, IBDV antigen was observed most intensely in bursa fabricius, thymus, bone marrow and to a lesser extent in spleen. Conclusion: In this study, in which the level of tissue damage and regenerative response due to IBDV vaccine were examined and interpreted in the poultry sector, where the most organized animal husbandry is carried out in our country, it was noted that the severity of necrosis remained moderate and the regenerative response was strong compared to classical high virulence IBDV vaccines. Adequate levels of primary follicle formation showing antigenic stimulation and B lymphocyte activation areas in the spleen were considered as an indication that the animals responded well to the vaccine virus. Key Words: Chick, Immunohistochemistry Infectious Bursal Disease Virus (IBDV), Pathology, Vaccination