Fig. 5

Faecal microbiota transplantation boosts gut germinal centres irrespective of age directionality. a–g 21-month-old C57BL/6 males were gavaged with faecal pellets from adult, 3-month-old mice. a Experimental outline (created by M. Stebegg) of faecal microbiota transplantation (FMT) where aged C57BL/6 males were given a suspension of faecal pellets from adult C57BL/6 donor mice by oral gavage. The cages of recipient mice were supplemented with fresh faecal pellets and dirty bedding from these donor mice once a week. The percentage and number of B220⁺Ki67⁺Bcl6⁺ germinal centre (GC) B cells (b, c), CD4⁺Foxp3^-CXCR5⁺PD-1⁺ Tfh cells (d, e) and CD4⁺Foxp3⁺CXCR5⁺PD-1⁺ Tfr cells (f, g) in Peyer’s patches (PPs) as quantified by flow cytometry. h–n 3-month-old C57BL/6 males were gavaged with faecal pellets from aged 21-month-old mice. (h) Experimental outline of FMT where adult C57BL/6 males were gavaged with faecal pellets from aged mice. The percentage and number of GC B (i, j), Tfh (k, l) and Tfr (m, n) cells in PPs were quantified by flow cytometry. Bar height corresponds to the mean, each circle represents one biological replicate. Bar plots show the combined results of 2 independent experiments with a total of n = 10–15 mice per group. P-values were determined using the Mann-Whitney test in GraphPad Prism6. Source data are provided as a Source Data file