Neutralizing antibody titers in sera of rabbits vaccinated with E3R4 alone or with Alum-MPL adjuvant.

Groups of 2 rabbits were immunized four times with E3R4 alone or with Alum-MPL adjuvant, and sera were collected at two weeks after the fourth immunization. Antisera of two rabbits (nos. 1 and 2) were tested for cross-neutralization of eight HPV pseudovirus types. Neutralization titers were determined as previously described [38], [39], [41].Abbreviations: Alum-MPL, Alum and monophosphoryl lipid A; HPV, human papillomavirus.