Intriguingly, however, 2000 pg/ml TGF-β1 at low infection levels significantly reduced infection intensity relative to controls in half of the data sets (Table 1; 1 vs 3 in Experiments 1–6), suggesting that control of infection by TGF-β1 may vary with P. falciparum oocyst load. Here, TGFB1 is linked to infection.