Fig. 1: The CTA1-DD adjuvant given through multiple routes targets the FDC network and enhances the GC reaction in draining lymph nodes.

a Microscopy sections from indicated tissues showing deposition of CTA1-DD or CTA1R7K-DD adjuvant at 6 h (i.v. and s.c.) or 24 h (i.n.) following immunization via different routes. FDC (Mfge8 or CD35, red), and CTA1-DD (green) were identified with laminin (blue) in spleen and B220 (blue) plus CD169 (cyan) in iLN. All images were taken with an inverted confocal microscope (LSM700) with x20 magnification. The size bars indicate 100 µm. These are representative sections from individual mice in groups of three mice showing similar results. b FACS analysis of antigen binding to FDC following immunizations with OVA-FITC alone or incorporated in the CTA1-OVA-DD fusion protein conjugated to AF488 and containing an equimolar dose (5 µg) of OVA-peptide. c IgG anti-NP-specific serum antibodies were determined by ELISA and given as log₁₀-titers ± SD after 2 i.v., s.c., or 3 i.n. immunizations as in a and b. These are pooled data from three experiments (n = 3 in each group). d The percentage of TFH cells (CD4⁺ FoxP3⁻ CXCR5⁺ PD-1⁺) or activated B cells (GL-7⁺ Fas⁺ IgD⁻ of all CD19⁺) in the GC in the mediastinal LN (mLN) (left panel) or inguinal LN (iLN) (right panel) was assessed by FACS 10 days following an i.n. (mLN) or s.c. (iLN) immunization with 5 µg NP-OVA with (black bars) or without (white bars) 10 μg admixed CTA1-DD adjuvant, as indicated. Cells from naive unimmunized mice (light gray bars) were included as controls (right panel). Statistical significance was determined by one-way ANOVA followed by Tukey correction for multiple comparisons; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.