Neonatal rotavirus infection: role of lacteal neutralising alpha1-anti-trypsin and nonimmunoglobulin antiviral activity in protection.

Expressed breast milks (EBMs) were collected from mothers of rotavirus (RV)-excreting babies and from mothers whose babies were RV free during an outbreak of asymptomatic RV infection in a newborn nursery to determine the role of lacteal anti-RV neutralising activity, alpha1-anti-trypsin activity, and nonimmunoglobulin antiviral factor in protection of neonates from RV infection, and although all of the above factors were present in the majority of the EBMs, no correlation could be found between their presence in EBM and protection from RV infection. A significant rise in both neutralising activity and subgroup 2 antibodies, was demonstrated in the EBM of one mother who experienced a subgroup 2 RV-associated diarrhoea during lactation. However, the alpha1-anti-trypsin activity and the nonimmunoglobulin antiviral levels remained the same. The importance of these factors in passive immunity with reference to virus dose is discussed.