Proteolytic Activity in Extracts of the Esophagus of Adults of Ancylostoma caninum and the Effect of Immune Serum on This Activity

Thorson, Ralph E.

doi:10.2307/3274611

Cited by 51 publications

(11 citation statements)

References 6 publications

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“…In support of this is the fact that dogs with repeated infections became immune to A. caninum infection (25), and sera from these dogs neutralized proteolytic enzyme activity in esophagea! extracts from the parasite (26,27). Presumably, during feeding ES products are introduced into the host and elicit protective antibodies.…”

Section: Discussionmentioning

confidence: 99%

Secretion of a proteolytic anticoagulant by Ancylostoma hookworms.

Hotez¹,

Cerami²

1983

The Journal of Experimental Medicine

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Hookworms of the genus Ancylostoma secrete an anticoagulant that both inhibits the clotting of human plasma and promotes fibrin clot dissolution. This anticoagulant activity is attributable to a 36,000 dalton proteolytic enzyme. The protease can degrade fibrinogen into five smaller polypeptides that intrinsically have anticoagulating properties, covert plasminogen to a mini-plasminogen-like molecule, and hydrolyze a synthetic peptide substrate with specificity for elastolytic enzymes. It is hypothesized that the parasite uses this enzyme to prevent blood clotting while feeding on villous capillaries.

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Section: Discussionmentioning

confidence: 99%

Secretion of a proteolytic anticoagulant by Ancylostoma hookworms.

Hotez¹,

Cerami²

1983

The Journal of Experimental Medicine

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“…[62][63][64][65] The latter 65 showed that this anticoagulant activity could be attributed to an elastase-like 36 kDa protease which could degrade ¿EULQRJHQ LQWR ¿YH VPDOOHU SRO\SHSWLGHV HDFK ZLWK DQWLFRDJXODQW SURSHUWLHV DQG FRQYHUW SODVPLQRJHQ WR D PLQLSODVPLQRJHQOLNH PROHFXOH 7KH SURWHDVH ZDV SXUL¿HG IURP DGXOW parasite extracts by several chromatographic steps, had optimal activity at pH 9-11 and was inhibited by EDTA, indicative of a metalloprotease. 66 The enzyme could degrade elastin and trypsin-labile glycoproteins in a rat vascular smooth muscle extracellular matrix.…”

Section: General Backgroundmentioning

confidence: 98%

“…2,3 Eye catching, from a vaccination point of view, were follow-up studies in the dog hookworm Ancylostoma caninum. Firstly, a study which demonstrated proteolytic activity in extracts of the oesophagus from the adult parasite that could be inhibited by immune serum 4 and another that showed the induction of acquired immunity in dogs by the injection of similar extracts. 5 Blood-feeding nematode pathogens digest haemoglobin as a source of nutrition 6 and the intestinal brush border is a rich source of proteases containing aspartyl, cysteinyl, metalloproteases as well as di-and aminopeptidases ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Proteases in Blood-Feeding Nematodes and Their Potential as Vaccine Candidates

Knox

2011

Advances in Experimental Medicine and Biology

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Parasitic nematodes express and secrete a variety of proteases which they use for many purposes including the penetration of host tissues, digestion of host protein for nutrients, evasion of host immune responses and for internal processes such as tissue catabolism and apoptosis. For these broad reasons they have been examined as possible parasite control targets. Blood-feeding nematodes such as the barber-pole worm Haemonchus contortus that infect sheep and goats and the hookworms, Ancylostoma spp. and Necator americanus, affecting man, use an array of endo- and exopeptidases to digest the blood meal. Haemoglobin digestion occurs by an ordered and partly conserved proteolytic cascade. These proteases are accessible to host immune responses which can block enzyme function and lead to parasite expulsion and/or death. Thus they are receiving attention as components of vaccines against several parasitic nematodes of social and economic importance.

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“…The infected animal is exposed to the metabolites of the nematode, to the materials released by the parasite during molting or following death, and in certain cases to different developmental stages of the worm. Metabolites of certain nematodes have been shown to be immunogenic (Soulsby, 1958;Thorson, 1956;Ewert and Olson, 1960), to contain a variety of antigens , to have various enzymes (review: Soulsby, 1958), to induce shock in nematode-infected animals (Sprent, 1951 ) and in gut segments from nematodeinfected or metabolite-injected animals Olson, 1961, 1962), but in spite of some chemical characterization (review: Weinstein, 1959), little is known of metabolites in terms of allergenicity. Extracts of adult or larval nematodes have been shown to contain a variety of antigens (Wodehouse, 1956;Kagan, 1957;Labzoffsky et al, 1959; al., Tanner and Gregory, 1961;Huntley and Moreland, 1963).…”

Section: Literature Reviewmentioning

confidence: 99%