CD8A and infection: S1B Fig shows the results for the transfer experiment performed on day 55. We next adoptively transferred isolated immune CD4+ and CD8+ T cells into C57BL/6 RAG1-/- mice later in infection on day 63, which is approximately 20–40 days prior to the usual onset of neurological symptoms. At this point in time the bacteria become detectable in the brain by qPCR. Fig 2A shows a schematic overview of the procedure. Control animals received PBS instead of T cells. Additional control groups of mice received either CD4+ or CD8+ T cells but were non-infected.