Figure 2. Tonsillar Nrp1⁺ CD4⁺ T cells support survival and Ig production of B cells in vitro.

(A) Flow cytometry analysis of Nrp1^- Tfh (CXCR5⁺ Nrp1^-: i), Nrp1⁺ Tfh (CXCR5⁺ Nrp1⁺: ii) and non-Tfh cells (CXCR5^- Nrp1^-: iii). (B-C) These three T cell subsets were cultured with B cells without exogenous stimulation, and compared for their ability to maintain B-cell survival after 5 days (B) and to induce the production of IgG, IgA and IgM (C) after 10 days of culture. Representative data from one out of four experiments are shown. Data were compared using Student’s impaired t-test (ns: not significant, *: p≤0.05, **: p≤0.01).