In published studies, HOCl-induced modifications were analyzed after treatment of peptides or proteins with a 0.5-25-fold molar excess of HOCl [18, [29] [30] [31] . As shown by Vossmann et al. [16] as well as in the present study, an antiviral activity of serum albumins was observed only after treatment of serum albumin with HOCl concentrations above the molar ratio of 1:100. Using lower HOCl concentration, e.g. 1:10 or 1:50 we were unable to detect any antiviral activity in our HIV-1 infection assays. This observation is important and demonstrates that HOCl modifications, which occur under low HOCl conditions [18, [29] [30] [31] might be totally different to those induced with higher HOCl concentrations as shown here. Another minor aspect is that we have modified albumin at concentrations ≤ 1 mg protein/ml. When serum albumin was treated with HOCl at higher concentrations, as described in the literature (10 mg/ml) [29] , we observed no inhibitory activity in our viral infection and syncytium assays (data not shown). Thus, based on our current knowledge, the antiviral activity of serum albumins was induced in diluted aqueous solution and only with a >100-fold molar excess of HOCl.