Prr13 was modestly expressed in naïve PbTIIs, and strongly upregulated by all PbTIIs and polyclonal counter parts (Fig 1Ai-iii and 1Bi-ii), with the magnitude and frequency of expression largely maintained by PbTIIs until day 28 post-infection and treatment (Fig 1Aii-iii). The gene discussed is PRR13; the disease is infection.