Immunity to Nippostrongylus brasiliensis infection in the rat

Jarrett, Ellen Elizabeth Evelyn (1968) Immunity to Nippostrongylus brasiliensis infection in the rat. PhD thesis, University of Glasgow.

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Infection of the rat with the nematode parasite Nippostrongylus brasiliensis provides a convenient laboratory model for the investigation of many aspects of the relationship between nematode parasites and their mammalian hosts. This is particularly so in the field of immunity where it is well established that primary infections with this parasite are terminated abruptly by an immunological reaction called the 'self-cure' and that subsequently rats are relatively immune to reinfection. Three aspects of the immunological response have been studied by the author. First the kinetics of worm populations in immune and normal rats, secondly the mechanisms responsible for the self-cure reaction and thirdly the characteristics of the immune response in immature rats. In Section 1 the quantitative aspects of establishment and expulsion of Nippostrongylus brasiliensis in the normal and immune rat are described. It is proposed that the kinetics of a primary infection may be described in 4 phases. These are: 1) Loss Phase 1 (LPl). After infection a proportion of the infecting dose of larvae fails to develop and is immobilised or destroyed before or during the course of migration via the lungs to the intestine, 2) The Plateau Phase, The remainder of the larvae develop to maturity in the intestine, their number remaining constant for a defined period of days. 3) Loss Phase 2 (LP2). This is synonymous with the self-cure reaction. During this phase the worms are expelled from the intestine of the host by an immunological mechanism. The onset of the expulsion is sudden but the process once initiated is exponential. Its rate is measurable in terms of the regression coefficient. This phase terminates when a threshold of worm numbers is reached. 4) Threshold Phase, This describes the residual population, usually of approximately 40 worms, which is not expelled and which survives for a fairly prolonged period. These four phases also occur in immune animals subjected to second or third infections but there are quantitative differences. With increasing numbers of infections the proportion of larvae destroyed during LP1 becomes greater, the Plateau is shortened and the expulsion rate of LP2 increases. It is suggested that the rate coefficient of this third phase is an accurate measure of the immune status of the animal. The Threshold Phase is of a similar order in first, second and third infections. These results are discussed with regard to their significance as measurements of the immune status of the host, their implication for the mechanism of helminth expulsion and their relevance to other helminth infections. Experiments undertaken to elucidate the mechanism of worm expulsion from the intestine are described in Section 2. (Abstract shortened by ProQuest.).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: G M Urquhart
Keywords: Parasitology, Immunology
Date of Award: 1968
Depositing User: Enlighten Team
Unique ID: glathesis:1968-72774
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 11 Jun 2019 11:06
Last Modified: 11 Jun 2019 11:06

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