Visualisation and characterisation of mononuclear phagocytes in the chicken respiratory tract using CSF1R -transgenic chickens

AbstractThe respiratory tract is a key organ for many avian pathogens as well as a major route for vaccination in the poultry industry. To improve immune responses after vaccination of chickens through increased uptake of vaccines and targeting to antigen presenting cells, a better understanding of the avian respiratory immune system is required. Transgenic MacReporter birds were used expressing a reporter gene (eGFP ormApple) under the control of theCSF1R promoter and enhancer in cells of the mononuclear phagocyte (MNP) lineage to visualize the ontogeny of the lymphoid tissue, macrophages and dendritic cells, in the trachea, lung and air sac of birds from embryonic day 18 –63 weeks of age. Small aggregates ofCSF1R-transgene+ cells start to form at the openings of the secondary bronchi at 1  week of age, indicative of the early development of the organised bronchus-associated lymphoid tissue. Immunohistochemical staining revealed subpopulations of MNPs in the lung, based on expression ofCSF1R-transgene, CD11, TIM4, LAMP1, and MHC II. Specialised epithelial cells or M cells covering the bronchus-associated lymphoid tissue expressedCSF1R-transgene and type II pneumocytes expressed LAMP1 suggesting that these epithelial cells are phagocytic and transcytose antigen. Highly organised lymphoid tissue was seen in trachea from 4  weeks onwards. Throughout the air sacs at all ages,CSF1R-transgene+ cells were scattered and at later stages,CSF1R-transgene+ cells lined capillaries. ...
Source: Veterinary Research - Category: Veterinary Research Source Type: research