FIG 5.
Activation of TFH-like cells in PBMC. (a) Representative plots show the increase of TFH-like cells (CD4+ CXCR5+ ICOS+) in PBMC following stimulation by LAIV for 3 days compared to their level in the medium control. (b) LAIV-induced increase in TFH-like cells in PBMC compared to the control level (n = 10; **, P < 0.01). (c) Anti-HA IgG and IgM antibody production in PBMC culture supernatant following LAIV stimulation (n = 10; **, P < 0.01). (d) Frequency of antigen-specific CD154+ TFH-like cells (% of CD4+ T cells; red bar) in PBMC following LAIV stimulation and subsequent sH1N1 antigen challenge compared to the frequencies of other CD4+ T cell subpopulations, as indicated (n = 4; **, P < 0.01; ***, P < 0.001).