Light-chain usage of PA anti-αIIbβ3 Abs. Platelet eluates were reacted with wt αIIbβ3-expressing 293T cells, followed by the incubation with FITC–anti-κ, PE–anti-λ, and APC–anti-CD61 Abs. Anti-κ (horizontal) and anti-λ (vertical) Abs bindings were analyzed in a subset of cells that were highly positive for CD61. Representative results of ≥ 2 independent experiments are shown.