Actinobacillus pleuropeumoniae is the bacterial
causative agent of porcine pleuropneumonia, a respiratory disease that affects
the swine industry worldwide. Proteases produced by animal pathogens show a
wide variety of biological actions in their hosts. Our group described that
A. pleuropneumoniae produces proteases
that degrade IgA, IgG, and hemoglobin. In this work, we report the obtaining of
a mutant of
A. pleuropneumoniae serotype 1 affected in its secretion of proteases and
the relationship between this deficiency and virulence. Materials and Methods
Proteases mutant of
A. pleuropneumoniae was obtained by chemical mutagenesis with NTG; it is
negative for proteolytic activity either the whole bacterium or its outer
membrane vesicles. The virulence potential of the mutant was evaluated: 1.
Proteolytic activity against porcine gelatin; 2. Adherence to buccal epithelial
cells and to low respiratory epithelium, the latter using a primary cell
culture model of porcine lung epithelial cells; 3. Hemolytic activity to sheep
and porcine erythrocytes.
The
protease mutant shows diminished the growth conditions and adherence to host
cells, whereas the hemolysins are present. Therefore, the mutant might be
explored in the use as immunogen against the swine pleuropneumonia.
The
first author is a doctorate student of the Academic Program in Biological
Sciences, Departamento de Sistemas Biológicos, UAM, México con No.208385202.