December 7, 2012

Breast milk blocks virus binding

Components of human breast milk help ward off viral infection, a new study shows.

Human breast milk’s infection-fighting properties are well known, but just how milk wards off viral infections has not been fully defined. Jason Iskarpatyoti, Terence Dermody, M.D., the Dorothy Overall Wells Chair in Pediatrics, and colleagues investigated the effects of human milk components on infection of cells with reoviruses – a family of viruses that causes mostly mild disease in mammals, but serves as a model for understanding viral pathogenesis.


They found that several milk components inhibit reovirus infection of host cells but that the effect differs depending on the strain of virus. Human milk gangliosides GD3 and GM3 inhibit infectivity of reovirus strain T3D by blocking its binding to host cells. In contrast, glucocerebroside (GCB) inhibits infectivity of reovirus strain T1L after the virus has attached. The strain-related differences are determined by a single viral gene, S1, which encodes the attachment protein of the virus.

The results, reported in the Nov. 25 issue of Virology, define a potential antiviral mechanism for human milk components and could help inform the selection of milk components for infant formula.

The research was supported by grants from Pfizer Nutrition.