Fig. 2

Oral treatment with colonization factor antigen 1 (CFA/I) fimbriae protects against the development of SjS. a Groups of 6-week-old SjS (5–8 mice/group) females were orally dosed with 5 × 10⁷ (− 1 or low dose), 5 × 10⁸ (− 2 or medium dose), or 5 × 10⁹ CFUs (− 3 or high dose) of Lactococcus lactis-CFA/I (LL-CFA/I), 5 × 10⁸ CFUs (medium dose) L. lactis (LL vector), or phosphate-buffered saline (PBS). Bacteria were grown in synthetic M17 medium supplemented with 0.5% glucose. Additional doses were administered to the mice every 3 weeks. b Saliva flow rate (SFR) measurements were taken prior to treatment, and 16 and 28 wks of age; *P < 0.05 versus 6-wk measurement. c Analysis at 28 wks of age show that low and medium doses of LL-CFA/I prevent reductions in SFR compared to PBS-treated mice; ***P < 0.001, one-way ANOVA followed by Dunnett’s multiple comparisons test was performed. d At 28 wks of age, submandibular glands were formalin fixed and stained with hematoxylin and eosin to determine extent of inflammatory cell infiltration. Representative images of stained tissues at ×20 magnification. e Infiltrated regions were drawn for area determinations and calculated by using the Aperio ImageScope software. Focus score of infiltrates were determined by using average focus size in area of foci in 4 mm²; *P < 0.05 versus PBS-treated mice. One-way ANOVA followed by Dunnett’s multiple comparisons test was performed. f Antinuclear antibodies (ANA)-positive mice from LL-CFA/I- and vector-treated mice compared to PBS-treated group; *P < 0.05. g–j For each sample, flow cytometry analysis for regulatory T cells (Tregs) was performed on 1 × 10⁶ lymphocytes isolated from mesenteric LNs (MLNs) after 1 week following the last treatment dose. g Percentages of CD4⁺ T cells were not significantly different amongst the treatment groups. The percentages of h Foxp3⁺CD4⁺, i CD25⁺CD4⁺, and j Foxp3⁺CD25⁺CD4⁺ T cells are depicted; *P < 0.05 relative to PBS- or LL vector-dosed mice