Pregnancy-associated serum N-glycome changes studied by high-throughput MALDI-TOF-MS.

Pregnancy requires partial suppression of the immune system to ensure maternal-foetal tolerance.
Protein glycosylation, and especially terminal sialic acid linkages, are of prime importance in regulating
the pro- and anti-inflammatory immune responses. However, little is known about pregnancyassociated changes of the serum N-glycome and sialic acid linkages. Using a combination of recently
developed methods, i.e. derivatisation that allows the distinction between α2,3- and α2,6-linked
sialic acids by high-throughput MALDI-TOF-MS and software-assisted data processing, we analysed
the serum N-glycome of a cohort of 29 healthy women at 6 time points during and after pregnancy. A
total of 77 N-glycans were followed over time, confirming in part previous findings while also revealing
novel associations (e.g. an increase of FA2BG1S1(6), FA2G1S1(6) and A2BG2S2(6) with delivery).
From the individual glycans we calculated 42 derived traits. With these, an increase during pregnancy
and decrease after delivery was observed for both α2,3- and α2,6-linked sialylation. Additionally, a
difference in the recovery speed after delivery was observed for α2,3- and α2,6-linked sialylation of
triantennary glycans. In conclusion, our new high-throughput workflow allowed the identification of
novel plasma glycosylation changes with pregnancy.