Figure 5. IL-2Jc-mediated protection is associated with impaired expansion of antigen-specific CD8⁺ T cells, reduced effector CD4⁺ T cell responses, and Treg cell expansion.

A) C57BL/6 mice were adoptively transferred with 10,000 CD8⁺ CD45.1⁺ OTI T cells, and infected with SIINFEKL-expressing transgenic PbTG. Control mice were infected with non-SIINFEKL-expressing PbG parasites. PbTG-infected mice were i.p. treated with IL-2Jc (day 0 or day 2), IL-2Sc (day 0), or control saline. On day 6 p.i., when control mice were displaying ECM symptoms, splenic CD8⁺ T cells (gated in FACS plots) were assessed for the presence of CD45.1⁺ SIINFEKL-specific T cells, and expression of the activation marker, GzmB. The graph indicates the number of CD45.1⁺ CD8⁺ SIINFEKL-specific T cells per spleen. Mann-Whitney * p<0.05. These data are representative of 2 independent experiments. B&C) C57BL/6 mice (n = 5) were infected with PbA, and i.p. treated with IL-2Jc (day 0 or day 2 p.i), IL-2Sc (day 0) or control saline. On days indicated, splenocytes were assessed directly ex vivo for the number of B) IFNγ-producing effector CD4⁺ T cells and C) CD4⁺ Foxp3⁺ Treg cells. Mann-Whitney: ***p<0.001. These data are representative of 2 independent experiments.