The Application of Magnetic Bead Selection to Investigate Interactions between the Oral Microbiota and Salivary Immunoglobulins

Abstract

The effect of humoral immunity on the composition of the oral microbiota is less intensively investigated than hygiene and diet, in part due to a lack of simple and robust systems for investigating interactions between salivary immunoglobulins and oral bacteria. Here we report the application of an ex situ method to investigate the specificity of salivary immunoglobulins for salivary bacteria. Saliva collected from six volunteers was separated into immunoglobulin and microbial fractions, and the microbial fractions were then directly exposed to salivary immunoglobulins of “self” and “non-self” origin. Antibody-selected bacteria were separated from their congeners using a magnetic bead system, selective for IgA or IgG isotypes. The positively selected fractions were then characterized using gel-based eubacterial-specific DNA profiling. The eubacterial profiles of positively selected fractions diverged significantly from profiles of whole salivary consortia based on volunteer (P≤ 0.001%) and immunoglobulin origin (P≤ 0.001%), but not immunoglobulin isotype (P = 0.2). DNA profiles of separated microbial fractions were significantly (p≤ 0.05) less diverse than whole salivary consortia and included oral and environmental bacteria. Consortia selected using self immunoglobulins were generally less diverse than those selected with immunoglobulins of non-self origin. Magnetic bead separation facilitated the testing of interactions between salivary antibodies and oral bacteria, showing that these interactions are specific and may reflect differences in recognition by self and non-self immunoglobulins. Further development of this system could improve understanding of the relationship between the oral microbiota and the host immune system and of mechanisms underlying the compositional stability of the oral microbiota.

Species-Level Salivary Microbial Indicators of Well-Resolved Periodontitis: A Preliminary Investigation

“…However, if no differences existed in the salivary microbiome assemblages between these two groups was unknown. The host-microbiome link is bi-directional, and as inherent features of oral microbiota affect immune programming (Madhwani and McBain, 2016), they may also associate with susceptibility to infection. A stable “core” oral microbial community structure that persists over years has been demonstrated (David et al, 2014) and such ecological stability is linked closely to an individual's salivary composition (Rosier et al, 2018).…”

The impact of the Th17:Treg axis on the IgA-Biome across the glycemic spectrum

“…e ., the SIgA-coated and SIgA-uncoated microbes) in the context of diabetes phenotypes because: i ) the oral cavity is the point of entry where microbes first encounter SIgA and some SIgA-coated taxa are present both in the oral cavity and the gut e . g ., Lactobacillus , Haemophilus , and Prevotella [ 15 – 17 ], and ii ) the impact of the Th17:Treg ratios in the context of the IgA-Biome and dysglycemia has not yet been explored and will better define the impact of the Th17:Treg/SIgA axis across mucosal microbiomes ( Fig 1 ).…”