Figure 9.
Selectivity of antibodies raised against a t-BuO-PEG conjugate of human serum albumin (t-BuO-PEG17-albumin) was assessed by direct ELISAs (A) and by competitive ELISAs (B). (A) Direct ELISAs were performed on assay plates coated with SOD coupled to 10 kDa HO-PEG (red ◆), to 10 kDa mPEG (black ◆), or to 10 kDa t-BuO-PEG (green ◆) . In this serum, from rabbit R12059, higher titers were detected with t-BuO-PEG-SOD than with mPEG-SOD or with HO-PEG-SOD. (B) Competitive ELISAs were performed on a 1/10 000 dilution of the same serum for which direct ELISA data are shown in (A) (rabbit R12059; filled symbols, solid curves) and on the same dilution of serum from a similarly immunized rabbit (R12060; open symbols, dashed curves). The results revealed a high degree of selectivity of these antisera for 10 kDa t-BuO-PEG (△, ▲) compared to 10 kDa mPEG (◇, ◆) or to 10 kDa PEG diol (○, ●).