A humanised mouse model of cytokine release: Comparison of CD3-specific antibody fragments

► Cytokine release seen with all OKT3 antibody constructs and fragments tested ► mIgG2a > hIgG1 (Ala-Ala) > hIgG1 DFM > hIgG1 F(ab′)2 > mIgG2a F(ab′)2 > hIgG1 Fab′ ► Complete depletion of human CD4 + and CD8 + T-cells seen with all constructs except Fab′ ► hOKT3γ1(Ala-Ala) induces small increases in IFNγ, TNFα and IL-10.