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Ontogenesis of the Chicken Bronchus Associated Lymphoid Tissue (BALT)
Author(s) -
Reese S.,
Dalamani G.,
Kothlow S.,
Kaspers B.
Publication year - 2005
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/j.1439-0264.2005.00669_93.x
Subject(s) - lymphatic system , biology , immune system , high endothelial venules , immunology , lung , lamina propria , epithelium , pathology , medicine , genetics
The avian lung shows fundamental differences to its mammalian counterpart and is characterized by a larger surface area and a thinner gas‐blood barrier. These features provide the morphological basis for the enhanced respiratory efficiency of the avian lung. However, they also predispose this organ to an increased risk of injury by pathogenic microorganisms. In order to investigate the host–pathogen interaction during pulmonary infection and vaccine delivery by aerosol immunization a detailed knowledge of the structure and ontogenesis of the bronchus associated lymphoid tissue (BALT) is required. For this reason the BALT of chickens aged from 1 day to 6 months was studied by immunohistochemistry (ICC), transmission (TEM) and scanning electron microscopy (SEM) as well as by FACS analysis. During the first 2 weeks after hatching no organized lymphatic structures were found. At this time, the defence system was based on the presence of cells of the unspecific innate immune system. In the third week after hatching lymphoid follicles begin to develop at the branching of primary and secondary bronchi. These develop into a highly organized bronchus associated lymphoid tissue (BALT) characterized by high endothelial venules and a follicle associated epithelium (FAE) with ‘M‐cell‐like’ cells. However, pathogens that have successfully crossed this initial barrier are additionally confronted with large numbers of lymphocytes and macrophages distributed around the parabronchi. Our results imply that the BALT is the first and most important structure encountering antigen and microbial pathogens, thus playing a central role in the initiation of a specific immune response.