Figure 6. Effect of blockage of CTLA-4 and PDL-1 on CD25^hi cells their suppression of anti-pneumococcal proliferative responses by CD4⁺ cells.

Purified CD25^hi cells were preblocked with anti-human CTLA-4 or anti-human PDL-1 blocking antibodies or isotype control (IgG) antibodies and added back to CD25^hi depleted MNCs (i.e. CD25^- cells) at the same original proportion and then stimulated with SPNT over 8 days and CD4⁺ cells proliferation analysed. Graph shows the mean percentage of proliferating CD4⁺ cells post SPNT stimulation in the anti-human CTLA-4 (a) or anti-human PDL-1 preblocked CD25^hi cells (b) groups (n = 5 each group). (*  = p <0.05).