Treg cell induction after depletion of platelets in vivo. F8^null(B6/129S) mice were infused with anti-GPIb antibody (R300) or isotype IgG control (C301) followed by rhF8 immunization. Blood samples were collected from retro-orbital bleed, and blood cell counts were analyzed using the scil Vet ABC Hematology Analyzer. Treg cells were analyzed by flow cytometry. (A) Representative flow cytometry plots. CD4⁺ cells were gated for CD25⁺ and Foxp3⁺ analysis. (B) CD4⁺CD25⁺Foxp3⁺ Treg cells at various time points after platelet depletion and rhF8 immunization. (C) The frequency of CD4⁺CD25⁺Foxp3⁺ Treg cells in peripheral blood. (D) The number of CD4⁺CD25⁺Foxp3⁺ Treg cells in peripheral blood 1 week after platelet depletion.