The vast majority of anti-gB antibodies did not show antiviral activity in in vitro assays. Among the seven donors that were tested comprehensively, the percentage of neutralizing antibodies among the gB binders ranged from 0% to 11% (mean 3%). Previous studies using adsorption of antibodies to gB have noted that in some individuals the overall neutralization capacity cannot be reduced, indicating that in these cases non-gB specific antibodies are major components of the neutralizing antibody response [18] . Repertoire analysis in other viral systems have also noticed an excess of binding versus neutralizing antibodies [44, 52, 53] .