One of the key aspects of the immune system is the ability to prime cells by vaccination. The γδ T lymphocytes represent a significant population of cells in the peripheral blood of cattle that have largely been ignored in this regard. Here we have explored the potential for WC1+ γδ T cells to be primed by vaccination. We hypothesize that the γδ T cells that exhibit a recall response in vitro following in vivo priming represent a unique population. Utilizing a Leptospira borgpetersenii vaccine, we examined the recall responses of WC1+ and CD4+ T cells to leptospiral antigen. The WC1+ γδ cells were the major responding population to antigen for the first few weeks following in vivo priming, with the CD4 T cell response only began to overtake them after a booster dose was administered. The primed WC1+ γδ T cells displayed a unique pattern of surface marker expression when stimulated with antigen compared to mitogen-stimulated cells, and which paralleled that observed on the CD4 T cells that responded to antigen. Additionally, chemokine receptor expression was assessed in both ex vivo and antigen-stimulated WC1 and CD4T cells. Ex vivo CD4+ and WC1+ T cells differed with regard to chemokine receptor transcript expression while the antigen-activated cells had very similar patterns of expression. Both subsets expressed genes typical of TH1-polarized cells, but differed with regard to transcripts for co-stimulatory molecules expressed. TCR usage by the antigen-responsive WC1+ γδ T cells from vaccinated animals was evaluated. The antigen-responsive cells had transcripts for several different Vγ and Vδ gene segments with very limited usage of J genes and highly variable CDR3 sequences. These results did not differ greatly from those obtained with nondividing cells or with ex vivo peripheral blood mononuclear cells suggesting little if any enrichment for a specific TCR type. These results support the hypothesis that WC1 + γδ T cells and CD4 αβ T cells that respond to leptospira antigen are likely to differ mainly with regard to how they are activated and the pathogen molecules that activate them, rather than with regard to their effector functions.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-4055 |
| Date | 01 January 2005 |
| Creators | Blumerman, Seth Lawrence |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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