Colostrum and Amniotic Fluid from Different Species Exhibit Similar Immunomodulating Effects in Bacterium-Stimulated Dendritic Cells

The fetus and newborn are immunologically immature. Bioactive compounds in amniotic fluid (AF) and maternal milk therefore play a key role in the immunological development of the infant intestine. We hypothesized that colostrum and AF exert similar immunomodulatory effects on the developing immune system. Hence, bone marrow-derived murine dendritic cells (BMDCs) were co-incubated with Clostridium perfringens A or Escherichia coli Nissle 1917 and porcine, bovine, or human AF, colostrum/milk whey fractions. Interleukin (IL) 10, IL-12, IL-6, and tumor necrosis factor-alpha (TNF-alpha) production was measured. IL-12 production was reduced with all AFs and wheys, and IL-6 and TNF-alpha were also reduced by porcine AF. Porcine and bovine whey both reduced TNF-alpha production. Overall, the reductions were most pronounced with the porcine fluids. Only bovine fluids caused strong induction of IL-10. Overall, effects of AF and whey from same species were similar. Viability of stimulated BMDCs was not significantly affected by the fluids. Neutralization of IL-10, transforming growth factor beta, and epidermal growth factor (EGF) did not remove the IL-12-inhibiting effect, but EGF neutralization increased IL-10 production. Addition of EFG to DCs enhanced the bacterium-induced cytokine production contrary to the effect of AF and colostrums, ruling out EGF as the inhibitory component in the fluids.