Fecal samples were vacuum-dried in a cooled
centrifuge and stored at 20 8C until further
preparation. Antibodies were extracted according to
the method of Haneberg et al. (1994). For detection of
fecal IgA MTPs were coated with antisera to porcine
IgA in a dilution of 1:250 (goat anti-porcine IgA,
AAI40, Serotec, Eching, Germany).