Figure 5.

Augmented Tfh differentiation and normal anti-influenza IgG levels in ICAM-1 and ICAM-2 deficient mediastinal lymph nodes. (A) Experimental design and timeline of Tfh cell generation and GC B cell accumulation post PR8-OVAII influenza infection. Donor WT CD45.1 OT-II splenocytes (10⁵) were I.V. transferred into WT and ICAM-1/2^-/- CD45.2 mice and mice were I.N. infected with a sublethal dose of PR8-OVAII influenza virus. 12 days post infection (dpi), MedLNs were harvested and the total number of (B) OT-II Tfh cells (CD4⁺CD44⁺CD62L^-PD-1⁺CXCR5⁺) and (C) GC B cells (B220⁺CD138^-CD38^-Fas⁺) were determined in the indicated MedLNs. I.N. PBS administration was performed in control experiments. (D) Experimental design and timeline for the flow cytometry analysis of OT-II Tfh cells (CD4⁺CD44⁺CD62L^-PD-1⁺CXCR5⁺) generated 12 days post infection in either WT (ICAM-1^fl/fl) or DC^ΔICAM-1 mice (top panel). Results shown (bottom panel) are the mean +- SEM. (E) Experimental design and timeline of the detection of PR8 specific IgG2a levels in the sera of PR8 infected mice (top panel). Sera were collected on day 12 post infection and the levels of PR8 specific IgG2a were determined in triplicates. Results shown (bottom panel) are the mean +- SEM. n= 3 for each group. Statistical significance was determined by two-tailed, unpaired Student’s t tests. *P < 0.05, **P < 0.01, ***P < 0.001, ns, not significant. The numbers of each experimental groups are indicated in the graphs. The error bars indicate the SEM of each measurement.