FCN2 and infection: Remarkably, the increase in C3-deposition in the presence of CRP and L-ficolin under infection-inflammation condition (pH 6.5, 2 mM calcium) was higher than the sum of the increased effect from either of the two individual proteins in the serum, demonstrating synergistic effect of the CRP∶ficolin interaction, and the enhancement of the complement activity against the invading bacteria.