A. Brown et al., Necator americanus (human hookworm) aspartyl proteinases and digestion of skin macromolecules during skin penetration, AM J TROP M, 60(5), 1999, pp. 840-847
Citations number
26
Categorie Soggetti
Envirnomentale Medicine & Public Health","Medical Research General Topics
The infective larvae of Necator americanus were shown to secrete all mechan
istic classes of proteolytic enzymes with two overall pH optima of 6.5 and
8.5 using fluorescein isothiocyanate-labeled casein as the substrate. Since
infective larvae are obligate skin penetrators, the effect of each of thes
e enzyme classes against macromolecules derived from human skin was examine
d. Larval secretions were shown to degrade collagen types I, III, IV, and V
, fibronectin, laminin, and elastin. All the skin macromolecules tested wer
e hydrolyzed by aspartyl proteinase activity, which was inhibitable by peps
tatin A. Collagen and elastin was also hydrolyzed by metalloproteinase acti
vity, while the serine proteinase activity hydrolyzed only elastin. As a co
nsequence of these experiments, the effect of proteinase inhibitors on the
penetration of live larvae through hamster skin was tested. Larval penetrat
ion was significantly inhibited only by pepstatin A, confirming the importa
nce of the aspartyl proteinase activity during the skin penetration process
.