IL33 and infection: Here, Ki67 immunostaining of neuron proliferation in the ventricle wall, showed a clear reduction of proliferating cells 7 days after PbA-infection in WT mice, while there was no reduction in infected ST2-/- mice (Fig 4A and 4B), suggesting that neurogenesis was preserved after PbA-infection in the absence of IL-33/ST2 pathway.