Samples of Fab fragment
were used to prepare Fab-[H.sub.2]O and Fab-[D.sub.2]O buffered stock solutions.
The specificity of the Fab antibody was measured by a sequential dilution of the Fab fragments
immobilized with 16peptide-BSA and BSA microplates as mentioned above.
The RecAll prostate-specific antigen (PSA)  assay, based entirely on site-specific recombinant Fab fragments
for capturing and detecting the analyte, has been demonstrated previously (9).
The small size of the Fab fragment
compared with the IgG molecule makes it more likely that nonspecific conjugation of the Fab fragments
will affect the antigen-binding site (50).
Serum samples collected from patients treated with Fab fragments
(with known unbound digoxin concentration as verified by ultrafiltration) can be used as controls for both ultrafiltration and direct measurements of unbound digoxin.
There have been cases in which severe overdose has been successfully treated with experimentally produced colchicine-specific Fab fragments
A 1:1500 dilution of antidigoxygenin-AP Fab fragments
(Roche) was then added, and the embryos were incubated overnight at 4[degrees]C and the reaction was allowed to proceed according to the kit manufacturer's instructions.
The Dower patent covers methods to display Fab fragments
using phage display technology and MorphoSys received a license for the Dower patent from Biosite in January 2000.
LABELING OF MABS AND FAB FRAGMENTS
WITH BIOTIN AND LANTHANIDE CHELATE
Incubation with antigen-digoxigenin was performed for 1 hr at 37[degrees]C, and after washing, 100 [micro]L/well peroxidase-conjugated sheep anti-digoxigenin Fab fragments
(Boehringer) diluted 1:3,000 in PBS/BSA-Tween 20 was added.
Thus, antibody affinity can be improved by in vitro maturation, i.e., mutation of the complementarity-determining regions of scFv or Fab fragments
. A substantial increase in affinity has been achieved by this approach (11), but the reported affinities have not been higher than those of the best native monoclonal antibodies.