Stimulation of PBMCs from all pregnant goats at day 0 (prior to infection) with C. burnetii NM for 4 hours resulted in a slightly lower mRNA expression of TLR4, the mRNA expression of TLR1 and TLR6 was slightly up-regulated, and the expression of TLR2 mRNA was strongly up-regulated in comparison with unstimulated PBMCs (Figure 2A). Here, TLR2 is linked to infection.