Article
The immune response during a Strongyloides ratti infection of rats.
School of Biological Sciences, University of Bristol, Bristol, UK.
Parasite Immunology (impact factor:
2.6).
08/2007;
29(7):339-46.
DOI:10.1111/j.1365-3024.2007.00945.x
Source: PubMed
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Article: Strongyloides ratti: dissociation of the rat's protective immunity into systemic and intestinal components.
Experimental Parasitology 01/1982; 52(3):386-95. · 2.12 Impact Factor -
Article: Host immune responses are necessary for density dependence in nematode infections.
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ABSTRACT: Nematode infections are subject to density-dependent effects on their establishment, survivorship and fecundity within a host. These effects act to regulate and stabilize the size of nematode populations. Understanding how these density-dependent effects occur is important to guide the development of control strategies against parasitic nematodes and the diseases that they cause. These density-dependent effects have been hypothesized to result from intraspecific competition between parasites for limited resources or from the action of host immune responses. However, no specific evidence exists to distinguish between these two hypotheses. We find that in nematode (Strongyloides ratti) infections, density-dependent effects on parasite establishment, survivorship and fecundity are mediated by the host immune response. These density-dependent effects are only observed late in primary infections and no density-dependent effects are observed in infections in immuno-compromised animals. We find no evidence for intraspecific competition between parasites in experimental infections over a range of doses that encompasses all that is observed in natural infections. We conclude that density-dependent effects due to the immune response will act to regulate S. ratti infections before competition for space or nutrients within the host gut ever occurs.Parasitology 10/2002; 125(Pt 3):283-92. · 2.96 Impact Factor -
Article: Criteria for a proof of migration routes of immature parasites inside hosts exemplified by studies of Strongyloides ratti in the rat.
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ABSTRACT: The first rigorous proof applicable to the migration pathway of an infective juvenile macroparasite inside its host is presented. Third-stage larvae of a homogonic strain of Strongyloides ratti applied in exact doses of less than 20 to the skin of the flank of young rats were recovered 16-40 h later in the naso-frontal part of the head. The peak proportion of the dose (po) recovered between 20 and 25 h in this site had a mean value of 0.316 +/- 0.021 in 48 animals. In 40 other rats infected simultaneously the mean proportion of the dose (pf) that reached the small intestine was at least 0.837 +/- 0.013. Proof resides in verification of the inequality po + pf greater than 1. With appropriate statistical tests the excess of the sum of the means of these two proportions over unity is shown to have a probability of occurring by chance of 1 in 3.5 x 10(6). Thus it is effectively certain that the naso-frontal portion of the head is part of at least one pathway taken by this parasite on its way from the skin to the intestine of its host. By suitable protection of the infection site it was confirmed that migration to the head was achieved by an internal route and not as a result of grooming. Larvae were recovered from the cranium in the same rats over the period 15-40 h, but the peak proportion of the dose occurred at 20 h, and po + pf less than 1 in this location. Whether the cranium is also part of the pathway is therefore still undecided. The significance of this novel analysis in the general context of in-host migration of infective stages is discussed and it is concluded, following its application to data sets from other authors, that the only cases in which proof can be demonstrated are the anterior skull of the rat for S. ratti (present data) and the lung of the same host for Nippostrongylus brasiliensis (Twohy, 1956).Parasitology 07/1988; 96 ( Pt 3):551-63. · 2.96 Impact Factor
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Keywords
greater concentrations
host immune response
IL-4
immune parameters
interferon-gamma
intestinal tissue
mesenteric lymph node
MLN
MLN cells
natural rat host
non-infected animals
Parasite-specific IgG(1)
parasite-specific immunoglobulin G(1)(IgG(1))
parasitic female antigen
primary infection
primary S. ratti infection
rat mast cell protease II
Strongyloides ratti
T-helper 2-type immune response
temporal changes
