Figure 6.

Frequency of CD4+ T follicular helper (Tfh) cells, germinal center B (GC B) cells and ASC elicited in the draining lymph node after NP (200 nm) immunization. Control animals were immunized with soluble Env or left naïve; all animals received the same total mass of Env antigen. All groups were immunized at day 0 and then boosted at day 21. Mice were sampled at day 3 and day 5 post-boost for Tfh, GC B cells and ASCs via flow cytometry and antigen specific B cell ELISpot assays. A) Left: frequency of Tfh cells (CD4⁺B220^-CD44^hiCXCR5⁺PD-1⁺), enumerated via flow cytometry. Center: frequency of GC B cells (CD19⁺CD4^-B220⁺CD138⁺Fas/CD95⁺GL7⁺), enumerated via flow cytometry. Right: Correlation between Tfh and GC B cell responses. Pearson test was performed assuming Gaussian distribution, with P and R² values shown. B) Left: the number of ASCs (CD19⁺CD4^-B220^loCD138⁺), measured by flow cytometry. Right: level of Env-specific IgG ASCs measured via antigen specific B cell ELISpot. In all panels, data for individual mice are shown, along with the mean and the standard deviation. Significance was determined between sparse NP and dense NP using the two tailed Mann-Whitney (t-test) analysis. * p<0.05