By 4 wk after i.m. prime or boost, CD69 was decreased on tet+CD8+ T cells from spleens, blood and
OUC, whereas its expression on the vagina was similar to that on unprimed CD8+ T cells. By 1 year after the boost, CD69 expression on tet+CD8+ T cells from all compartments was similar to that of naïve cells, suggesting that this molecule is unlikely to contribute for the sustained presence of vaccine-induced CD8+ Selleckchem Y27632 T cells within the GT (data not shown). Expression of CD127 was increased on tet+CD8+ T cells from ILN and the vagina at 4 wk after priming. A similar pattern was observed at 4 wk after the boost but for a modest increase in OUC. By 1 year after the boost, CD127 expression was increased in tet+CD8+ T cells from all compartments, being especially pronounced in cells from GT. The most striking difference in the expression of CD103 was seen at 1 year after the boost, when this marker was markedly upregulated on tet+CD8+ T cells from the GT, but otherwise comparable to naïve cells in the other compartments. No remarkable changes were seen in the profile of NKG2D on T cells from the compartments analyzed. Figure 4B shows the expression levels of granzyme
B, a proteolytic enzyme that induces caspase-dependent apoptosis, Selleck Raf inhibitor and perforin, a pore-forming protein that facilitates granzyme access through the membrane into the cytosol of the target cell 19. In
addition, Fig. 4B shows the expression levels for CTLA-4, a key molecule for downregulation of T-cell responses, Acyl CoA dehydrogenase programmed death-1 (PD-1), which negatively regulates T-cell signaling and effector functions and is expressed at increased levels on so-called exhausted T cells 20 and Ki-67, a protein associated with proliferation. Expression of granzyme B mostly mirrored that of perforin, with a very pronounced increase in both enzymes in most tet+CD8+ T cells isolated from the whole GT at 1 year after the boost. Notably, the expression levels of other markers such as CD62L at the same time point suggest that T cells isolated from the GT had differentiated into resting memory cells. Memory CD8+ T cells typically do not carry granzyme or perforin, which are markers for fully activated effector CD8+ T cells. CTLA-4 expression was decreased in tet+CD8+ T cells from spleens, ILN and vagina at 4 wk after the prime, whereas there was an increase in its expression on those from OUC.