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Floss-Based Vaccination and IgA Protection

1:10:50 recording · AUTO · 4 speakers

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Brief overview

Floss-delivered vaccine protects mice, and human milk IgA limits a Th17-inducing gut bacterium in infants.

  1. Floss can carry vaccine antigen into the gum creviceAntigen-coated flat floss tape delivered 59% of a 100-microgram dose to the human gingival sulcus and protected mice against influenza challenge.
  2. The route looks systemic, not mucosalSalivary IgA was not raised, so the hosts read the effect as antigen crossing to the blood through flossing microtrauma rather than true mucosal immunisation.
  3. Milk IgA restrains one Th17-inducing infant gut microbeSecretory IgA from high-binding milk blocked E. ramosum adherence to gut epithelial cells and the IL-17 pathway it switches on.
Executive Summary AI
  • Steph Langell presents a Nature Biomedical Engineering paper, first author Rohan Ingrill and last author Harvinder Singh Gill of Texas Tech, NC State and UNC Chapel Hill, in which vaccine antigen is coated on flat floss tape and used to floss the two front teeth of a mouse, targeting the permeable junctional epithelium at the base of the gingival sulcus.4:50
  • With a CPG adjuvant the floss raised serum and mucosal responses and protected mice in an influenza challenge better than an intranasal vaccine, though salivary IgA barely moved, suggesting antigen is mainly crossing to the systemic compartment through the microtrauma of flossing.20:56
  • In healthy volunteers aged 18 to 50 using a commercial floss pick coated with blue food dye, 59% of the 100-microgram coating reached the gingival sulcus and 56% of participants flossed between 2 and 11 times (five passes most common), while 67% said they would be more inclined to take flu or coronavirus vaccines this way; the hosts flag user error and the paper's line that it only works for indiv22:55
  • Vincent Racaniello then covers a PNAS paper from Brett Finley's group at University of British Columbia, first author Catherine Donald, using the Canadian CHILD cohort of 300 mother-infant pairs to ask which infant gut bacteria human milk secretory IgA (one to eight grams per liter) targets.27:32
  • E. ramosum was the only species negatively associated with secretory IgA targeting, and IgA purified from 20 high-binding milk samples blocked its adherence to intestinal epithelial cells and the Th17-driving cytokine programme, while heat-denatured or low-binding IgA did not and the bacterium does not adhere in mice at all, which limits mechanistic work.47:49
Key Quote
“You cannot do intense Psycom and have a lab.”
— Vincent Racaniello3:40
Key Quote
“how do you set up a oral vaccine or a mucosal vaccine and make sure that it doesn't lead to a tolerance response?”
— Brianne Barker9:22
Key Quote
“I think there's some significant challenges with actually implementing this, but I really love the creativity of it.”
— Cindy Leifer25:05