A. Vandekerkhof et al., INFLUENCE OF ACTINOBACILLUS-PLEUROPNEUMONIAE AND ITS METABOLITES ON PORCINE ALVEOLAR EPITHELIAL-CELLS, Infection and immunity, 64(9), 1996, pp. 3905-3907
The effect of Actinobacillus pleuropneumoniae and its metabolites on t
he viability of porcine alveolar epithelial cells was studied by using
a neutral-red uptake test. Alveolar epithelial cells were obtained fr
om 5-week-old colostrum-deprived pigs. The purity of these cells as as
sessed by the modified Papanicolaou stain was 90 to 95%. Incubation of
these cells with 10(6) CFU of a biotype 1 serotype 1 strain resulted
in death of the alveolar epithelial cells within 1.5 h. A cytotoxic ef
fect was also seen when alveolar epithelial cells were incubated with
sterile culture supernatants of biotype 1 serotype 1, biotype 1 seroty
pe 10, and biotype 2 serotype 2 strains or with ApxI, AprII, or ApxIII
produced by recombinant Escherichia coli. Incubation of alveolar epit
helial cells with a knockout mutant of the biotype 1 serotype 1 parent
strain which is unable to secrete Apx toxins or with its supernatant
did not result in death of these cells. These results indicate that cy
totoxicity is at least in part due to production of Apx toxins.