High efficient mammalian expression and secretion of a functional humanized single-chain Fv/human interleukin-2 molecules

Figure 5 Determination of antigen-binding activity of H520C9sFv-hIL-2 fusion protein. Antigen binding activity was measured by indirect ELISA using cultured SKOV 3ip1. Bound fusion protein was recognised with the anti-human IL2 polyclonal antibody EP100. The fusion proteins, H520C9sFv-hIL-2 and H520C9sFv-mhIL-2 were shown to bind to p185 positive cells SKOV 3ip1. A chemically-conjugated molecule containing the intact parental 520C9 mAb and rhIL-2(520C9-rhIL-2) was used as a positive control. As a negative control, mouse IgG failed to show any binding activity. The data are the mean ± SD from three separate experiments. ^bP < 0.01 vs mouse IgG; ^bP < 0.01 for 520C9-rhIL-2 vs H520C9sFv-hIL-2 and H520C9sFv-mhIL-2; ^dP < 0.01 vs mouse IgG; ^aP < 0.05 for 520C9-rhIL-2 vs H520C9sFv-hIL-2 and H520C9sFv-mhIL-2.