Although the LTβR-dependent fold changes observed in MSC gene expression, and in lymphoid and myeloid cell production, were relatively small (<threefold), these were nevertheless physiologically important given that mice became more susceptible to systemic infection with Listeria monocytogenes (Fig 3H), which is consistent with a prominent role of monocytes in defense against systemic L. monocytogenes infection (Serbina et al, 2008). Here, LTBR is linked to infection.