Studies on human lacteal rotavirus antibodies by immune electron microscopy.

In vitro studies carried out by immune electron microscopy (IEM) indicate that rotavirus aggregation detected in the stools of newborn breast-fed infants with rotavirus infection is antibody-induced. Aggregation of rotavirus particles occurred with the IgA-containing fraction of expressed breast milk (EBM) obtained five days postpartum and with the IgA- and IgG-containing fractions of a pool of EBMs containing samples collected 2-3 days postpartum. Bovine milk fractions also demonstrated this activity in the IgG- and IgA-containing fraction. Studies on unfractionated EBMs from a mother who experienced a rotavirus infection during the 43rd week of lactation showed that following rotavirus infection all three major classes of rotavirus-specific antibodies were present in breast milk, this being confirmed by enzyme immunoassay.