[HTML][HTML] Activation-Induced Cytidine Deaminase Expression in CD4+ T Cells is Associated with a Unique IL-10-Producing Subset that Increases with Age

H Qin, K Suzuki, M Nakata, S Chikuma, N Izumi… - PloS one, 2011 - journals.plos.org
H Qin, K Suzuki, M Nakata, S Chikuma, N Izumi, L Thi Huong, M Maruya, S Fagarasan…
PloS one, 2011journals.plos.org
Activation-induced cytidine deaminase (AID), produced by the Aicda gene, is essential for
the immunoglobulin gene (Ig) alterations that form immune memory. Using a Cre-mediated
genetic system, we unexpectedly found CD4+ T cells that had expressed Aicda (exAID cells)
as well as B cells. ExAID cells increased with age, reaching up to 25% of the CD4+ and
B220+ cell populations. ExAID B cells remained IgM+, suggesting that class-switched
memory B cells do not accumulate in the spleen. In T cells, AID was expressed in a subset …
Activation-induced cytidine deaminase (AID), produced by the Aicda gene, is essential for the immunoglobulin gene (Ig) alterations that form immune memory. Using a Cre-mediated genetic system, we unexpectedly found CD4+ T cells that had expressed Aicda (exAID cells) as well as B cells. ExAID cells increased with age, reaching up to 25% of the CD4+ and B220+ cell populations. ExAID B cells remained IgM+, suggesting that class-switched memory B cells do not accumulate in the spleen. In T cells, AID was expressed in a subset that produced IFN-γ and IL-10 but little IL-4 or IL-17, and showed no evidence of genetic mutation. Interestingly, the endogenous Aicda expression in T cells was enhanced in the absence of B cells, indicating that the process is independent from the germinal center reaction. These results suggest that in addition to its roles in B cells, AID may have previously unappreciated roles in T-cell function or tumorigenesis.
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