Figure 3. Inhibitory action of anti-pneumococcal responses by regulatory T cells.

Inhibition of mucosal CD4⁺ T cell anti-pneumococcal responses to Ply (a) and SPNT (b) but not to flu (c) by CD25^hi regulatory T cells in subjects above 16 years old as indicated by increased cell proliferation following depletion of CD25^hi cells from tonsil MNC population is observed. Subjects (n = 50) were grouped into those aged less than 17 yrs, 17 to 25 yrs and >25 yrs. Individual subject's proliferative response pre and post CD25^hi cell depletion are shown with a connecting dashed grey line, while solid black bars and black dashed line represent mean proliferative values for undepleted and CD25^hi cell depleted populations. (*  = p <0.05).