Orf is a highly contagious, eruptive skin disease of sheep and goats caused by a parapox virus. The virus enters through abrasions in the skin, where it replicates in the regenerating epidermal keratinocytes. Despite the generation of a specific antiviral response, orf virus reinfections can be established easily, although the lesions are milder and generally regress more rapidly than after primary exposure. The cutaneous response to orf involves the formation of a dense network of MHC class II<SUP>+</SUP> dendritic cells at the lesion. The primary aim of this project was to characterise these dendritic cells and to identify the cytokines produced by orf infected keratinocytes <I>in vitro</I>, that might be involved in the accumulation of the dendritic cells <I>in vivo</I>. <I>In vivo</I> studies of primary and secondary orf virus lesions identified the class II<SUP>+</SUP> dendritic cells to be a population of CD1<SUP>-</SUP> cells, which are also found within the dermis of normal ovine skin. A subpopulation of these cells also expressed the antigen, coagulation factor XIIIa. Factor XIIIa<SUP>+</SUP> dendritic cells comprised over half the dendritic cells seen in the network of a primary orf lesion but were only observed in small numbers, transiently, in the secondary orf lesion. All the dendritic cells lacked the expression of ovine macrophage markers. The proliferative response of the primary and secondary orf lesions also differed. High proliferative activity was observed in the epidermis and dermis in the primary response to orf but not in the secondary response. A few of the proliferating cells were identified as dendritic cells but it would appear that the dendritic cell network in both primary and secondary orf lesions does not arise by local cell division.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:653742 |
| Date | January 1995 |
| Creators | Lear, Andrea |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/20625 |
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