MPO and infectious meningitis: All transcripts identified in human meningitis CSF were upregulated in GBS-infected larvae at the time when GBS enters the brain (18−24 hpi), including tumor necrosis factor (TNF), interleukin-1β (IL-1β), interleukin-8 (IL-8), granulocyte-colony stimulating factor (G-CSF), matrix metalloproteinase-9 (MMP9), matrix metalloproteinase-13 (MMP13) and myeloperoxidase (MPO) [50,51] (Fig 6J–6P).