Washing the assay plate with Tween 20 or Tween 80, detergents
that
contain HO-PEG, decreased the titers detected by direct ELISAs of
sera from rabbits immunized with HO-PEG-uricase (○, ●)
or mPEG-uricase (Δ, ▲) and amplified the differences
between the titers of anti-PEG antibodies detected in sera from these
two rabbits. Direct ELISAs with mPEG-SOD as the antigen were performed
as described in Experimental Procedures, except
that the PBS used to wash one of the replicate assay plates before
and after the addition of the enzyme-linked secondary antibody contained
either 0.05% (v/v) Tween 20 (A) or 0.1% (v/v) Tween 80 (B). Higher
titers were detected in the absence of detergent (filled symbols,
solid curves) than in the presence of Tween (open symbols, dashed
curves). The effects of each type of Tween on the results for the
individual rabbits immunized with either HO-PEG-uricase or mPEG-uricase
are shown by red arrows and black arrows, respectively. The ratios
of titers detected in sera from these two rabbits in the presence
or absence of Tween are shown by blue arrows.