Nasal IgA-seq

Defense of the nasal mucosal barrier through secretory IgA (sIgA) is critical to protect from infection and to maintain homeostasis of the microbiome, which influences respiratory disorders and hosts opportunistic pathogens. To identify which bacterial genera and species are targeted by sIgA on the level of the individual host, IgA-seq analysis was applied on nasal microbiota samples from healthy volunteers. Nasal bacteria were obtained using nasal swabs and stained with fluorescently labelled anti-IgA, thereby labelling pre-deposited sIgA on the bacteria in their native state. The bacteria were subsequently sorted by FACS according to their fluorescence into sIgA-positive and sIgA-negative fractions. Both sorted fractions, as well as the non-sorted samples, were analyzed by 16S rRNA gene sequencing to determine species composition and enrichment in the sorted fractions.