I would appreciate informations on the following subjects.
1) Are T cells really matures when they leave the thymus? If yes, how to
explain the induction of T cell anergy in periphery? It is generally
imputed to the absence of a second signal given by antigen presenting
cells. Could it be due to the absence of molecules in T cells which are
only expressed or secreted after they leave the thymus. This could let the
time to T cells directed against self antigens to encounter self antigens
in periphery, and be functionnally inactivated or deleted. In this way
only T cells directed agains non-self antigens would develop.
2) I try to understand the mechanism of tolerance against indigenous
bacteria. Is it more easy to induce oral tolerance at birth? Are
indigenous bacteria when they colonize the digestive tract immidiatly
after birth encounter a fully developed mucosal and systemic immune
system?
Thanks in advance
Harold Marcotte
Marc.Lavoie at bcm.ulaval.ca
