Title page for ETD etd-07282008-144043


Document Type Doctoral Thesis
Author Pretorius, Alri
Email pretoriusac@arc.agric.za
URN etd-07282008-144043
Document Title Aspects of the immune response in ruminants to four protective Ehrlichia Ruminantium gene products
Degree PhD
Department Veterinary Tropical Diseases
Supervisor
Advisor Name Title
Prof B A Allsopp Co-Supervisor
Dr N E Collins Supervisor
Keywords
  • Ehrlichia ruminantium gene products
Date 2007-11-23
Availability unrestricted
Abstract
In the search for a better vaccine against Ehrlichia ruminantium infection in ruminants, four E. ruminantium open reading frames (ORFs) derived from the Welgevonden isolate were tested using either DNA vaccination or DNA primemodified viral or DNA prime-recombinant protein boost strategies. Both the DNA vaccination and the DNA prime.recombinant protein boost strategy provided complete protection against E. ruminantium Welgevonden needle challenge, while the DNA prime.modified viral boost strategy only provided 90 % protection. The DNA prime.recombinant protein boost strategy also coincided with elevated cellular immunology as was evident from increased IFN- production. Furthermore, we could show that the 1H12 DNA vaccine could induce protection against heterologous needle challenge when animals were immunised with the Welgevonden-derived 1H12 ORFs and challenged with selected E. ruminantium stocks. Unfortunately the DNA only and the DNA prime.recombinant protein boost strategy were not protective in the field. Therefore, our results suggest that there is a vast difference between needle challenge and natural tick infestation and that E. ruminantium organisms transmitted by ticks have the ability to evade the protective immunity induced by immunization with the four 1H12 ORFs.

2007 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Pretorius, A 2007, Aspects of the immune response in ruminants to four protective Ehrlichia ruminantium gene products , PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-07282008-144043/ >

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