Lymph node cells from mice which have undergone primary cutaneous sensitization (responder cells) were cultured with either in vitro haptenated cells or hapten-bearing dendritic cells from hapten sensitized mice. By utilising the fluorescent hapten FITC and flow cytometry the stimulator cells hapten status was established and related to any enhancement in responder cell proliferation. In vitro haptenation failed to generate immunogenic hapten presenting cells but rather, hapten-coated cells whose stimulatory activity, while hapten-specific, was dependent on a silica-sensitive cell within the 'responder' population. The inadequacy of in vitro haptenated cells as a model for hapten presentation was thus established and a role for endogenous hapten processing cells is proposed. Hapten-bearing dendritic cells from hapten-sensitized mice were used as stimulators within the proliferation assay. Such cells were prepared (on density gradients) from FITC-sensitized mice and characterised in terms of morphology and flow cytometric parameters: these results correlated with a marked stimulatory activity for responder cells. Avoidance of potent sensitizing regimes enabled the isolation of dendritic cell-enriched fractions with hapten-specific stimulatory activity. Significantly, this activity could not be created by in vitro haptenation of naive dendritic cells. I concluded that the stimulatory activity of in vivo 'haptenated' dendritic cells within my proliferation assay was a good model for hapten presentation in vitro. Finally I examined the ability of in vivo administered, partially purified IFN gamma preparations (and relevant controls) to modulate cutaneous sensitization and in particular the generation of immunogenic dendritic cells. While not all the effects detected were IFN gamma specific, the changes measured in the hapten status and resulting stimulatory activity of dendritic cell-enriched fractions were so. Proposals areĢ made as to how antigenically foreign proteins and lympnokines, including IFN gamma, may regulate the role of dendritic cells in cutaneous sensitization.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:293641 |
| Date | January 1991 |
| Creators | Jones, David Allan |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/108062/ |
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