Table 1 Binding parameters for anti-IsdB x anti-C1q.

From: A novel bispecific antibody platform to direct complement activity for efficient lysis of target cells

Capture Surface

Test ligand

Biacore kinetic parameters for anti-IsdB x anti-C1q bispecific antibody binding to IsdB and C1q at 37 °C

ka (M−1s−1)

kd (s−1)

KD (M)

T1/2 (min)

anti-IsdB x anti-C1qa

IsdB.6xHis

1.63 × 105

5.57 × 10−4

3.43 × 10−9

21

anti-IsdB bivalenta

IsdB.6xHis

3.65 × 105

6.40 × 10−4

1.75 × 10−9

18

Biotinylated hC1qb

anti-IsdB x anti-C1q

1.79 × 105

8.71 × 10−2

4.78 × 10−7

0.13

IsdB.6xHis) + anti-IsdB x anti-C1qc

Human C1q

1.05 × 106

5.13 × 10−3

4.90 × 10−9

2.3

  1. Anti-IsdB x anti-C1q bsAb binds to C1q with low affinity and IsdB with high affinity. This bsAb was produced with one arm recruiting C1q and the other arm targeting the IsdB antigen present on the surface of S. aureus. The bsAb was characterized using Biacore.
  2. aIsdB.6xHis was injected across an Fc-captured anti-IsdB x anti C1q chip surface.
  3. banti-IsdB x anti-C1q bsAb was injected across a streptavidin-captured biotinylated human C1q chip surface.
  4. canti-IsdB x anti-C1q bsAb and human C1q were sequentially injected across a chip surface of captured IsdB.6xHis protein.
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