Early life intestinal immunity in pigs

Claudin-4 (green) is normally localized between epithelial cells in the gut (right). In the piglet jejunal epithelial cells at birth, Claudin-4 is localized to the apical tips of the cells (left). This unusual localization of Claudin4 may contribute to the leaky gut state of the newborn piglet. (Images by J.A. Pasternak and H.L. Wilson; Pasternak, J. A., et al. (2015), Mediators Inflamm 2015: 263629.)

Project Team: Heather L. Wilson, Brodie Deluco, Siew Hon Ng

In utero, piglets do not share circulation with the sow and therefore do not receive maternal antibodies. Piglets are born immunologically naïve and must ingest colostrum to receive passive immunity. The piglet gut was reported as semi-permeable for several days after birth, but research from our lab shows it remains permeable to for less than 24 hours after birth. The reason for this change may be a result of breeding for piglets that gain weight quickly. This semi-permeable status facilitates the uptake of colostrum-derived cells and macromolecules (e.g. antibodies, cytokines, antimicrobial peptides, etc.) across the gut wall. After this brief period of time, the gut undergoes a maturation process and is no longer semi-permeable.

We intend to understand the physiological and biological changes that take place in the piglet gut during the transition from a semi-permeable to a 'closed' state. We have identified changes in the localization of proteins that maintain the Tight Junctions between the gut wall epithelial cells within the first days of life. These changes may contribute to the transition from a semi-permeable gut to a mature gut.

This program is focused on determining the basic biology behind changes in gut permeability after birth, and to determine the mechanism of maternal cells/macromolecules uptake across the gut wall. Once the mechanism of but maturation is known, it is our intent to capitalize on this knowledge to promote vaccine uptake across the gut wall.