Fig. 1

Distribution of CD45⁺ cells in calves lymphoid pharyngeal tissues (Waldeyer’s ring), 60 min after intranasal administration of S. aureus-conjugated FITC. After nasal administration with S. aureus-conjugated FITC (SA-FITC) or cCHP nanogel-SA-FITC complexes, FITC⁺/CD45⁺ mononuclear cells of Waldeyer’s ring, spleen, and mesenteric lymph node in calves were evaluated by flow cytometry. a Transversal section (plane indicated as B) of Waldeyer’s ring and route of administration with SA-FITC or cCHP nanogel/SA-FITC complexes. b Location of the pharyngeal tonsils (a), paired tubal tonsils (b), paired palatine tonsils (c), and lingual tonsil (d). c Gating scheme for the identification of CD45⁺ leukocytes based on forward and side light scatter characteristics of tissue monocytes. d Dot plot showing the percentage of FITC⁺/CD45⁺ mononuclear cells in pharyngeal tonsils (a), paired tubal tonsils (b), paired palatine tonsils (c), lingual tonsil (d), spleen, and mesenteric lymph node. Black circles correspond to nasal immunization with cCHP nanogel/SA-FITC complexes, grey circles to nasal immunization with SA-FITC, and white circles to non-immunization controls. *Significant difference between the mean of each group (P < 0.05)