Binding of HOCl-modified serum albumins to gp120. (a-f) Binding of HSA, BSA, MSA and HOCl-modified albumins mHSA, mBSA, mMSA (protein:HOCl molar ratio 1:1000) to LAV-gp120 was tested by surface plasmon resonance spectroscopy (Biacore 1000, GE Healthcare). Purified LAV gp120 (10 μg/ml, Protein Sciences Corporation) was covalently linked using EDC/NHC to a dextran coated, CH-activated sensor chip (CM5, GE Healthcare). After blocking with ethanolamine the biosensor was washed three times with 30 μl 100 mM NaOH and 30 μl 100 mM HCl (flow rate 5 μl/min). Proteins were tested for binding at 1, 5, 10, 25 and 50 μg/ml at a flow rate of 5 μl/min. (g). Binding of mHSA, mBSA and mMSA (values marked by the black arrow in Figure 1a, 1c and 1e) was compared to the binding of CD4, and gp120-specific antibodies to a LAV gp120 coated CM5 biosensor. ADP429: anti-serum, derived from HIV-1 SF2 gp120-immunized sheep (AIDS reagent project, NIBSC, UK). EVA3047: monoclonal antibody, derived from IRIQRGPGRAFTIGC-peptide immunized mice (AIDS reagent project, NIBSC, UK).