Enhanced immunogenicity of a recombinant genital warts vaccine adjuvanted with monophosphoryl lipid A

The regression of genital warts is believed to be a T-cell-mediated immune effect. We have sought to enhance the immunogenicity of a therapeutic vaccine for the treatment of genital warts with the use of the adjuvant monophosphoryl lipid A (MPL^®-immunostimulant), a detoxified form of the lipopolysaccharide (LPS) of Salmonella minnesota R595. The comparative immunogenicity and reactogenicity of a recombinant human papillomavirus type 6 (HPV6) L2E7 fusion protein in either aqueous, oil-in-water emulsions or Alhydrogel^® formulations containing MPL^® was evaluated. We conclude that the simple addition of MPL^® to the L2E7 fusion protein already adsorbed onto Alhydrogel^® preferentially enhances antigen specific in vitro T-cell proliferative responses, IFNγ production and in vivo delayed type hypersensitivity responses without increasing its reactogenicity.