Quantitative determination of macromolecular transport rate across intestinal Peyer's patches.

We used horseradish peroxidase (HRP) (mol wt, 40,000) to compare in vitro, in Ussing chambers, the rates of protein transport across segments of piglet jejunum with and without Peyer's patches. The mean HRP transport rate across intestinal segments with a patch, 25.2 +/- 4.2 SE ng . min-1 . cm-2 (22 animals), was increased threefold (P less than 0.0005) compared with control (no patch) tissue, 7.9 +/- 1.0 ng . min-1 . cm-2 (n = 29). Neither rate showed saturation with increasing concentrations of HRP; both were inhibited 75-95% by a temperature drop from 37 to 15 degrees C. Transport across patch-containing tissue was inhibited 48 +/- 6% (n = 5, P less than 0.0025) by 1 mM NaF, but NaF had no consistent effect on the transport across tissue without Peyer's patches. We conclude that HRP transport is increased across Peyer's patches. This transport is dependent on metabolism and does not involve specific receptors. These findings support the concept that the Peyer's patch serves an antigen-sampling function in the gut.