Fig. 6: Pten-deficient platelets preferably form aggregates and physically interact with CD4⁺ T cells in the lymph nodes.

The pLNs from 6-month-old mice were subjected for analysis (a–d). The platelets from 3-month-old mice were subjected for analysis (f). a, b Distribution of platelet aggregates in the pLNs from Rosa26^mT/mGPf4-Cre and Rosa26^mT/mGPten^fl/fl Pf4-Cre mice (Scale bars, 100 µm). T-cell zone is visualized by B220-negative area (a). Quantifications of the number (Rosa26^mT/mGPf4-Cre, n = 4; Rosa26^mT/mGPten^fl/fl Pf4-Cre, n = 5) and size (Rosa26^mT/mGPf4-Cre, n = 3; Rosa26^mT/mGPten^fl/fl Pf4-Cre, n = 5) of platelet aggregates in the PLNs (b). c Direct contact between platelets and CD4⁺ T cells in T-cell zone of pLNs (Scale bars, 100 µm). d The existence of Pten-deficient platelets in the germinal centers which identified by PNA-positive clusters and circled by while line (Scale bars, 20 µm). e The diagram showing the transfer of GFP-labeled WT (Pten^+/+) and Pten-deficient platelets (Pten^−/−) into WT mice. f Location of transferred Pten^+/+ GFP⁺ platelets and Pten^−/− GFP⁺ platelets in the lymphoid tissues of recipient mice. The blood vessel and lymphatic vessel are indicated by CD31 positive (red) or LYVE-1positive (purple) region in pLNs of recipient mice. Cell nuclei were counterstained with DAPI (blue) (Scale bars, 100 µm). g Quantifications of the number (WT, n = 6; Pten-deficient, n = 5) and size (n = 5) of transferred WT and Pten-deficient platelet aggregates. h An illustration showing aberrant Th and Tfh cell responses caused by Pten-deficient platelets and potential underlying mechanisms. Results are representative of at least three independent experiments, and data (b, g) are presented as mean ± s.e.m. (two-tailed t test). Source data are provided as a Source Data file.