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

tel-00827710, version 1 - 29 May 2013
of antigen, a factor also known to modulate immune responses. Due to the combination of
these factors, previous studies have demonstrated that treatment efficiency depends on the
form of antigen and the route of immunization (Abadie et al., 2009).
(b) Probability that antigen-presenting DCs encounter antigen-specific
T cells
Once the antigen is processed and presented on the DC surface, these cells will next interact
with antigen-specific T cells. This meeting occurs in lymphoid organs where T cells and DCs
are present at very high numbers. This concentration of cells increases the probability that
antigen-presenting DCs encounter the correct antigen-specific T cells. As described earlier,
the frequency of antigen-specific T cells can be artificially increased in experimental systems
via adoptive transfer, allowing for a more rapid encounter between the two cell types. Other
circumstances such as a prior exposure to this antigen and presence of memory antigen-
specific T cells can also influence the rate of the subsequent response to the same antigen.
Figure 14. Factors influencing the outcome of CD8 + T cell responses.
(c) Microenvironment
Although the probability that the different actors of the immune response interact together in a
steady state has already been discussed, the microenvironment is often modified by infection,
tumor growth or adjuvant administration resulting in altered inflammatory or
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