Recombinant ifnα

Example 21

In this example, it is shown that both Mask1 and Mask2 of the disclosure can reduce and restore IFNα activity. Briefly, HEK Blue IFNa/b cells (Invivogen) were seeded into 96-well tissue culture plates (Fisher) at a density of 1×10e4 cells/well (50 uL/well). 50 uL/well of recombinant IFNα (Novus Biologicals) or indicated Abs (5T4 or Mesothelin) were incubated with the cells at the indicated concentrations overnight at 37 deg. C. Abs cleaved with MST14 (R&D Systems) were prepared by incubating 50 ug of Ab with 0.5 ug of MST14 for 1 hr. At 37 deg. C. Then, 10 uL of supernatant was added to a plate containing 90 uL/well Quanti-Blue substrate (Invivogen). Absorbance changes were read at 630 nm using a Biotek EPOCH ELISA reader. The results show that the IFNα activity in masked anti-CD138-IFNα (Mask1) and masked anti-CD138-IFNα (Mask2) was reduced compared to when the mask is cleaved. (See, FIG. 32(A) & FIG. 32(B)).

Example 6

In this example, it is shown that a plurality of Masked Fusion Abs of the disclosure can reduce and restore IFNα activity. Briefly, HEK Blue IFNa/b cells (Invivogen) were seeded into 96-well tissue culture plates (Fisher) at a density of 1×10e4 cells/well (50 uL/well). 50 uL/well of recombinant IFNα (Novus Biologicals) or indicated Abs (5T4 or Mesothelin) were incubated with the cells at the indicated concentrations overnight at 37 deg. C. Abs cleaved with MST14 (R&D Systems) were prepared by incubating 50 ug of Ab with 0.5 ug of MST14 for 1 hr. At 37 deg. C. Then, 10 uL of supernatant was added to a plate containing 90 uL/well Quanti-Blue substrate (Invivogen). Absorbance changes were read at 630 nm using a Biotek EPOCH ELISA reader. The results show that the IFNα activity in masked anti-5T4-IFNα and masked anti-mesothelin-IFNα was reduced by approximately 1 to 2 logs compared to when the mask is cleaved. (See, FIG. 7(A) & FIG. 7(B)).

Example 17

A study of the functional characterization of QXL138AM was performed using the following protocol. Briefly, HEK Blue IFNa/b cells (Invivogen) were seeded into 96-well tissue culture plates (Fisher) at a density of 5×10e4 cells/well (50 uL/well). Then fifty (50) uL/well of recombinant IFNα (Novus Biologicals) or indicated Abs were incubated with the cells at the indicated concentrations overnight at 37 deg. C. Abs cleaved with MST14 (R&D Systems) were prepared by incubating 50 ug of Ab with 0.5 ug of MST14 for 1 hr. At 37 deg. C. Ten (10) uL of supernatant was then added to a plate containing 90 uL/well Quanti-Blue substrate (Invivogen). Absorbance changes were read at 630 nm using a Biotek EPOCH ELISA reader. The results show (i) The Fusion Ab targeted IFNα is a potent as the wild type IFNα, (ii) the Non-Targeted Ab-IFNα is approximately 100× less potent that wild type IFNα, (iii) the mask is effective at blocking Non-Targeted IFNα, and (iv) the mask reduces IFNα activity even when targeted to transformed (non-tumorigenic) HEK cells expressing CD138. (See, FIG. 23(A) & FIG. 23(B)).