Studies characterising the immunoglobulin (Ig)-bound microbiota apply varying methodologies making comparisons difficult to assess.This scoping review synthesized evidence on Ig-microbiota binding patterns in maternal and infant contexts, identified recurrent Ig-bound and -unbound bacteria across studies, and knowledge gaps for further study.Nine articles investigating Ig-microbiota binding patterns in stool or breastmilk samples in mothers or infants were included.Ig-microbiota associations were influenced by sample type, Ig subclass, genetics and diet.The most important antibody was IgA, with partial functional redundancy with IgM, while IgG appeared more selective for pathobionts.Ig-bound taxa in early life included important commensals and pathobionts, with high levels of individuality.Ig-microbiota associations shifted with microbiome maturation along with environmental and host factors, resembling adults at around 2 years of age.Transfer of Igbound Bifidobacterium through breastmilk may contribute to vertical transmission from mother to infant.Ig-microbiota associations also differed between health and disease states, beyond the overall microbiota.Results were limited by study numbers and lack of methodological consistency.We propose the standardised term 'Ig-Seq' in referring to the technique to study Ig-microbiota binding patterns, and suggest standardisation of laboratory protocols, bioinformatic pipelines, and statistical analyses to improve consistency of results in Ig-Seq.
Tan et al. (Mon,) studied this question.