Interestingly, despite lower peripheral parasitaemia, the expression of granzyme B and KLRG1 by splenic CD8+ T cells was enhanced rather than decreased in 4X compared with 1X infected IgMi mice, suggesting that that CD8+ T cell activation during repeated PbA infections was not directly proportional to peripheral parasite burden (Figures 6B,E). The gene discussed is GZMB; the disease is infection.