Demonstration of Taenia crassiceps cysteine proteinase activity in tegumentary lysosome-like vesicles

Amal I. Khalil, Alan R. Burns, A. Clinton White

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Larval stages of Taenia species survive for prolonged periods in the tissues of their intermediate hosts. Other groups have demonstrated that host immunoglobulins are taken up by the cysticerci by adsorptive endocytosis, degraded, and the amino acids incorporated into parasite proteins. We have shown that a 43-kDa cysteine proteinase is the major parasite enzyme that degrades immunoglobulin in vitro. To localize this enzyme in situ, Taenia crassiceps cysticerci were incubated with the peptide substrate Z-Phe-Arg- methoxynaphthylamide. Free methoxynaphthylamide was coupled to p-rosanilin and osmium and visualized by transmission electron microscopy. Initial studies of cysticerci incubated without substrate confirmed the normal microanatomy and absence of significant host inflammation. In comparison to controls with no substrate, sections of cysticerci incubated with substrate revealed electron-dense deposits in round vesicles. The vesicles were found primarily within the tegumentary cytons and internuncial processes, a location similar to that described for vesicles associated with adsorptive endocytosis. There were proportionately more endocytotic vesicles and electron-dense vesicles in smaller cysticerci than larger ones. Formation of electrondense deposits was inhibited by heat and partially inhibited by the cysteine proteinase inhibitor E-64. These data are consistent with localization of the cysteine proteinase activity to lysosome-like vesicles.

Original languageEnglish (US)
Pages (from-to)513-515
Number of pages3
JournalJournal of Parasitology
Volume84
Issue number3
DOIs
StatePublished - Jun 1998
Externally publishedYes

Fingerprint

Taenia crassiceps
Cysticercus
cysticerci
Taenia
Cysteine Proteases
cysteine proteinases
lysosomes
vesicle
Lysosomes
endocytosis
substrate
Endocytosis
immunoglobulins
Immunoglobulins
Parasites
electrons
Electrons
parasite
Cysteine Proteinase Inhibitors
Osmium

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Parasitology
  • Microbiology

Cite this

Demonstration of Taenia crassiceps cysteine proteinase activity in tegumentary lysosome-like vesicles. / Khalil, Amal I.; Burns, Alan R.; White, A. Clinton.

In: Journal of Parasitology, Vol. 84, No. 3, 06.1998, p. 513-515.

Research output: Contribution to journalArticle

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