2B). However when Ad85A was administered in 5–6 μl, either alone or as a boost after BCG, no effect on mycobacterial load was detected in lung or spleen ( Fig. 2A and B). We and others have shown previously that protection against M.tb after Ad85A i.n. immunisation correlates with the presence of activated CD8+ find protocol antigen-specific

cells in the lungs. We therefore examined the phenotype of antigen-specific cells in the lungs after immunisation with 5–6 or 50 μl of Ad85A. Antigen-specific IFNγ+ CD8+ cells were identified as either effector (CD62L− CD127−), effector memory (CD62L− CD127+) or central memory (CD62L+ CD127+) phenotype [9] and [22]. Immunisation with Ad85A in 50 μl induced significantly higher numbers of both effector and effector memory cells than 5–6 μl and a greater proportion were

effector cells ( Table 2). Too few antigen-specific cells were present in the NALT after either immunisation to obtain reliable phenotypic data. We further characterised differences in response to 5–6 or 50 μl immunisation with Ad85A by determining the number of cells producing TNFα, IFNγ and IL-2. ICS was performed on lung cells that had been stimulated with the same mix of CD4 and CD8 peptides and the number of cytokine producing cells was determined. For each of the three cytokines, immunisation with 50 μl Selleck INCB018424 induced a greater response than immunisation with 5–6 μl (Fig. 3A). As polyfunctional antigen-specific T-cells have been reported to be important in protection against several diseases including M.tb [23] and [24], we assessed what proportion of antigen-specific cells were single (1+), double (2+) or triple (3+) cytokine producers ( Fig. 3C). Immunisation with 50 μl induces a greater proportion of single cytokine producing CD8+ T-cells than immunisation with 5–6 μl and this difference is made up of cells producing IFNγ only ( Fig. 3C). Another cytokine shown to play a role in the immune response to M.tb Electron transport chain is IL-17 [25] and [26]. ICS was performed on lung cells that had been stimulated with the mix of CD4 and CD8 peptides and the frequency of IL-17 producing cells determined. Lungs

from mice immunised with 50 μl of Ad85A show a significantly greater number of CD8+ IL-17+ cells than those from mice immunised with 5–6 μl ( Fig. 4). There is a trend towards fewer CD4+ IL-17+ cells in lungs from mice immunised with 6 μl, however the absolute number of CD4+IL17+ cells is extremely low, so this data should be treated with caution (data not shown). IL-17 expression was not detected in the NALT. The role of the URT associated lymphoid tissue in protection against respiratory infections remains unclear. In a pneumococcal challenge model, cauterisation of the NALT did not affect protection induced by intra-nasal vaccination [14]. However, the cauterisation was performed on infant mice and at this stage NALT development may not be complete [14].