Figure 3: cTfh cells at day 7 post-TIV react to multiple influenza antigens.

The CD154 assay was performed with PBMCs at day 7 and day 60 post-TIV and overlapping peptide libraries derived from hemagglutinin (HA), neuraminidase (NA), nucleoprotein (NP), matrix protein 1 and 2 (M1, M2), nonstructural protein 1 and 2 (NS1, NS2), polymerase proteins (PA, PB1, PB2) of the 2009 pandemic H1N1 strain. PBMC samples were obtained from at least 4 subjects and two assays were performed per sample on different days (indicated by closed and open symbols). The frequency of CD154⁺cytokine⁺ cells within CXCR5⁺CD4⁺ T cells and CXCR5⁻CD4⁺ T cells is indicated. (a) The CD154 assay was performed with PBMCs at day 7 and day 60 post-TIV and overlapping peptide libraries. The frequency of CD154⁺cytokine⁺ cells within CXCR5⁺CD4⁺ T cells is indicated. Mann-Whitney test. p-value ** < 0.01, *** < 0.001. (b) The results of the CD154 assay performed with PBMCs at day 7 and day 60 post-TIV and influenza vaccine (Fluzone^®) or control (cont. PBS). The frequency of CD154⁺cytokine⁺ cells within CXCR5⁺CD4⁺ T cells and CXCR5⁻CD4⁺ T cells is indicated. (c) The results of the CD154 assay performed with PBMCs at day 7 and 60 post-TIV and overlapping peptide libraries. The frequency of CD154⁺cytokine⁺ cells within CXCR5⁻CD4⁺ T cells is indicated.