Trichinella spiralis and the Concept of Niche

Trichinella spiralis is an intracellular parasite as both a larva and an adult. The first-stage larva lives in a modified portion of a skeletal muscle cell, the nurse cell, and can reside there for the life span of the host. Adult worms occupy a nonmembrane-bound portion of columnar epithelium, livi...

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Bibliographic Details
Published in:The Journal of parasitology 1993-08, Vol.79 (4), p.472-482
Main Author: Despommier, Dickson D.
Format: Article
Language:English
Subjects:
Animals
Cell nucleus
Female
Host-Parasite Interactions
Infections
Intestine, Small - parasitology
Larva - growth & development
Larva - immunology
Larva - physiology
Larvae
Larval development
Male
Mammals - parasitology
Mice
Mice, Nude
Muscle larvae
Muscles - parasitology
Nurses
Parasite hosts
Parasites
Parasitology
Rats
Symposium: Immunoecology of Host-Parasite Interactions
Trichinella spiralis - growth & development
Trichinella spiralis - immunology
Trichinella spiralis - physiology
Trichinellosis - immunology
Trichinellosis - parasitology
Worms
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Summary:Trichinella spiralis is an intracellular parasite as both a larva and an adult. The first-stage larva lives in a modified portion of a skeletal muscle cell, the nurse cell, and can reside there for the life span of the host. Adult worms occupy a nonmembrane-bound portion of columnar epithelium, living there as intramulticellular parasites. The newborn larva is the only nonintracellular stage, living free in the circulation. Trichinella spiralis induces modifications in each of its intracellular niches. Parasite signals secreted into the milieu of the developing nurse cell results in the reprogramming of host genomic expression, reflected in loss of muscle-specific proteins, over-expression of collagen, and the development of a circulatory rete. Formation of the nurse cell is complex, presumably involving many steps; yet there is not a large series of related intermediate forms in nature. Trichinella pseudospiralis induces an incomplete nurse cell. Adult parasites cause the death of the infected epithelium. The precise nature of most of the signals from parasite to host and from host to parasite has not been determined. As a direct consequence of exposure to some of them, the host develops long-lasting immunity to reinfection. This may confer advantages both for the parasite, as well as the host, because strong immune responses should reduce intraspecific competition.
ISSN:0022-3395
1937-2345
DOI:10.2307/3283370