Hoffmann-La Roche Inc.

F. Hoffmann-La Roche Ag

Manuel Endesfelder

Michael Molhoj

Joerg Moelleken

Christian Gassner

Joerg-Thomas Regula

Thomas Joerg Regula

Herein is reported a method for determining the binding affinity of the binding sites of a bivalent full length antibody of the human IgG1 subclass to a homo-multimeric antigen comprising the steps of i) incubating a mixture comprising the antibody and a polypeptide that is derived from lysine-gingipain ofat a pH of from pH 7.5 to pH 8.5, in the presence of a reducing agent, at a temperature of from 30° C. to 42° C., for time of from 10 min. to 240 min. to cleave the antibody into Fabs and Fc-region, and ii) determining the binding affinity of the Fabs of the antibody for its antigen using a surface plasmon resonance method by directly applying the incubated reaction mixture obtained in the previous step in the surface plasmon resonance method and therewith determining the binding affinity of the binding sites of the bivalent full length antibody of the human IgG1 subclass.

Direct affinity measurement of human IgG1 binding multimeric antigens

Herein is reported a method for determining the binding interaction with a multimeric antigen of an antibody of the human IgG1 subclass that has at least two binding sites specifically binding to the antigen comprising the steps of 1) determining the binding affinity of the antibody for the multimeric antigen, and 2) incubating a mixture comprising the antibody and a polypeptide that is derived from lysine-gingipain ofunder conditions and for a time sufficient to cleave the antibody into Fabs and Fc-region, and determining the binding affinity of the Fabs of the antibody for the multimeric, whereby the binding affinity of the antibody to the multimeric antigen to be affinity-driven if the binding affinity determined in both steps are comparable and to be avidity-driven if the binding affinity determined in both steps are different.

Method for determining the in vivo interaction mode

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Wessling, Germany

Manuel Endesfelder