Voie d'immunisation et séquence d'administration de l ... - TEL

tel-00827710, version 1 - 29 May 2013
splenocytes derived from K bm1 mOva mice were inoculated into WT recipients. These cells
express a membrane-bound ovalbumin as an antigen and display a mutated K b molecule
ensuring cross-presentation and not direct presentation of antigen.
To avoid the requirement for TCR-transgenic T cells, we optimized the previously described
technique of tetramer-based enrichment to detect low numbers of endogenous antigen-specific
T cells (Moon et al., 2007). We combined this strategy with additional techniques, such as
intracellular staining or immunoscope, in order to perform an in-depth phenotypic and
functional analysis of the tetramer-positive T cell population. This approach was then applied
to compare the efficiency of cross-priming following systemic dissemination of cell-
associated antigen upon intravenous injection or local administration by intradermal injection.
Antigen-specific T cells generated from these two types of injection were compared for their
proliferative capacity, quantity, polyfunctionality, re-stimulation properties, diversity and
affinity. Furthermore, we also studied the persistence of cell-associated antigen and antigen
cross-presentation in order to explain the differential immune responses observed between the
two routes of immunization.
II. DEFINING THE OPTIMAL TIMING OF ADJUVANT
DELIVERY
While adjuvants have been shown to be useful for enhancing the response to an antigen, it has
been observed that adjuvant delivery prior to immunization can actually result in inhibitory
effects (Wilson et al., 2006).
Following the results obtained by comparing the two routes of immunization, particularly in
regards to the kinetics of the T cell response, we were interested to ask whether the route of
immunization impacts the optimal timing of adjuvant delivery. Poly I:C was used as adjuvant,
as it is known to induce type I IFN secretion. The adjuvant was delivered at various time
points prior to, during or after immunization with cell-associated antigen. We observed
various effects of adjuvant on antigen presentation, priming and the resulting CD8 + T cell
response, depending on the timing of administration. In an attempt to further dissect the
mechanism of these time-dependent differential effects, we investigated the role of type I IFN
in these phenomena. Specifically we examined which cells type I IFN are acting on, in order
to modulate T cell cross-priming.
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