Figure 4.

T-bet promotes TFH cell expansion in a T cell intrinsic manner. (A) Setup of Bone marrow chimera mice. Bone marrow cells from WT (CD45.1⁺) and Tbx21^−/− (CD45.2⁺) mice were mixed in 7:3 ratio and adoptively transferred into lethally irradiated recipient WT (CD45.1⁺) mice. After bone marrow reconstitution, recipients were infected with LCMV (Armstrong strain). Spleens were harvested at day8 post infection. (B–D) Representative flow cytometry of TFH cells (CD44⁺CXCR5⁺) (B), tetramer-positive CD4⁺ T cells (C) and tetramer-positive TFH cells (D) in WT and Tbx21^−/−. Bone marrow derived cells (left), and the summary of percentages and ratio (by comparing the T-bet^−/−: WT ratio in target cells and total CD4⁺ T cells) of these cell subsets (right). Numbers adjacent to outlined areas indicate percent of each cell subset in parent subset. ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001 (paired two-tailed t-test). Data are representative of two independent experiments with 6 or 9 chimera mice.