Nrp1⁺ T cells are not proliferating and have no regulatory activity.

<p>(A) Ki67 expression in tonsillar CD3⁺ CD4⁺ Nrp1^- and Nrp1⁺ T cells. Five tonsils were analyzed and the expression data was compared with a Student’s paired t-test (**: p≤0.01). (B) The regulatory function of Nrp1⁺ Tfh cells was tested in coculture experiments with CFSE-labeled non-Tfh cells as described in Materials and Methods. The percentage of non-Tfh cells having diluted CFSE after 5 days of culture with various ratios of Nrp1⁺ Tfh cells was analyzed by flow cytometry. Data pooled from three distinct experiments are summarized here.