Norovirus-specific immunoglobulin A in breast milk for protection against norovirus-associated diarrhea among infants.

Hannah Karen Mina Labayo, Monica J. Pajuelo, Kentaro Tohma, Lauren A. Ford-Siltz, Robert H. Gilman, Lilia Cabrera, Holger Mayta, Gerardo J. Sanchez, Anniuska Toledo Cornejo, Caryn Bern, Clyde Dapat, Tomonori Nochi, Gabriel I. Parra, Hitoshi Oshitani, Mayuko Saito

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background: Norovirus (NV) causes acute gastroenteritis in infants. Humoral and fecal immunoglobulin A (IgA) responses have been correlated with protection against NV; however, the role of breast milk IgA against NV infection and associated diarrhea is still unknown. This study aimed to evaluate the protective role of NV-specific IgA (NV-IgA) in breast milk. Methods: Ninety-five breast milk samples collected from mothers enrolled in a 2016–2017 Peruvian birth cohort study were tested for total IgA and NV-IgA by ELISA using GII·4 variants and non-GII·4 genotype virus-like particles (VLPs). Breast milk samples were grouped according to the NV infection and diarrheal status of infants: NV positive with diarrhea (NV+D+, n=18); NV positive without diarrhea (NV+D-, n=37); and NV negative without diarrhea (NV-D-, n=40). The percent positivity and titer of NV-IgA were compared among groups. The cross-reactivity was estimated based on the correlation of ratio between NV-IgA against GII·4 variants and non-GII·4 genotype VLPs. Findings: NV-IgA had high positivity rates against different VLPs, especially against GII (89–100%). The NV+D- group had higher percent positivity (89% vs. 61%, p=0·03) and median titer (1:100 vs 1:50, p=0·03) of NV-IgA than the NV+D+ group against GI·1 VLPs. A relatively high correlation between different GII·4 variants (0·87) and low correlation between genogroups (0·23–0·37) were observed. Interpretation: Mothers with high positivity rates and titers of NV-IgA in breast milk had NV infected infants with reduced diarrheal symptoms. Antigenic relatedness to the genetic diversity of human norovirus was suggested.

Original languageEnglish (US)
Article number100561
StatePublished - Oct 2020


  • Breast milk
  • Diarrhea
  • Immunoglobulin A
  • Maternal immunity
  • Norovirus

ASJC Scopus subject areas

  • Medicine(all)


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