Respiratory tract infections with bacteria like Actinobacillus pleuropneumoniae are
extremely common in pigs and are of major veterinary relevance. The respiratory tract can
be divided into the upper part, consisting of the nose, pharynx, larynx and trachea, and the
lower part, consisting of the different parts of the lung. After bronchoscopy and
bronchoalveolar lavage (BAL) had been established for pigs, interest grew in the unspecific
parts of the immune system of the respiratory tract (such as macrophages, mast cells, the …