Figure 8

Photomicrographs of hematoxylin-and eosin-stained lung sections of chickens on 8^thday post-challenge. Chickens (n = 17 in each group) were intranasally vaccinated with empty CNPs, CNPs delivering antigens in both protein (Pr) and mRNA formats (CNPs + mRNA + Pr) or CNPs delivering antigens in protein (Pr) format only (CNPs + Pr) and 3 weeks later chickens were boasted with the same dose and route. At 28 days post-first vaccination, all the vaccinated chickens were challenged with 10⁴ TCID₅₀ of either H7N9 or H9N2 virus. Chickens that received empty CNPs showed hyperemia with infiltration of mononuclear inflammatory cells in bronchi and lung parenchyma, while birds vaccinated with CNPs delivering antigens in protein format only showed significantly lower inflammatory lesions than CNPs alone. Lungs of chickens vaccinated with CNPs delivering antigens in both formats appeared like that of the uninfected lungs. Scale bar = 100 µM. Each picture is representative of 6 chickens. Black arrows indicate fluid filed areas of the lung tissues and yellow arrows represent macrophages infiltrated in the lung tissues due to infection.