First detection of IgA against norovirus in breast milk.

Abstract

Breast milk samples (n = 239) collected from 1994-1997 from mothers at Chiba City, Japan, were tested for antinorovirus antibody by ELISA and western blot methods. It was found that 31 breast milk samples contained IgA against norovirus and this represented 13%. Breast milk could react with a diversity of norovirus genotypes. The highest number of samples containing IgA against norovirus was found in genotype GII/6 (11.3%) and the lowest in GI/8, GII/8 and GII/12 (each of 0.8%). Of note, twenty-eight samples showed reactivity to more than one different norovirus genotypes. Interestingly, three samples demonstrated cross-reaction with both norovirus genogroups I and II. This report is noteworthy because it is the first, to the best of our knowledge, demonstrating the presence of antibody against norovirus in breast milk.