Liposome-stabilized oil-in-water emulsions as adjuvants: increased emulsion stability promotes induction of cytotoxic T lymphocytes against an HIV envelope antigen.
Protective or therapeutic immunity against HIV infection is currently believed to require both antibody and CTL responses against the envelope protein. In the present study, the adjuvant activity of a unique oil-in-water emulsion, in which liposomes containing lipid A (LA) and encapsulated antigen served as the emulsifying agent, was examined in mice using oligomeric gp140 (ogp140) derived from the HIV-1 envelope as the antigen. Emulsions rendered either highly stable or unstable by altering the ratio of liposomes to oil were used to examine the effect of stability of the emulsion on adjuvant activity. Stable and unstable emulsions had similar potencies for inducing both IgG antibodies to ogp140 and antigen-specific T-lymphocyte proliferation. Stable emulsions, but not unstable emulsions, induced antigen-specific CTL responses, possibly because of the depot effect of the stable emulsions. Furthermore, stable emulsions induced lower IgG2a/IgG1 ratios than the unstable emulsions. We conclude that stable liposomal oil-in-water emulsions provide an effective means of obtaining both antibody and CTL responses against an HIV envelope antigen.
Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA. Roberta.Owens@na.amedd.army.mil
Roberta L
RL
Richards
Mangala
M
Rao
Thomas C
TC
Vancott
Gary R
GR
Matyas
Deborah L
DL
Birx
Carl R
CR
Alving
D016915:AIDS Vaccines / Q000008:administration & dosage / Q000737:chemistry / Q000276:immunology*; D000276:Adjuvants, Immunologic / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D004355:Drug Stability; D004655:Emulsions / Q000737:chemistry / Q000494:pharmacology; D015488:HIV Antigens / Q000008:administration & dosage / Q000276:immunology*; D019302:HIV Envelope Protein gp160 / Q000008:administration & dosage / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis; D008081:Liposomes; D051379:Mice; D008807:Mice, Inbred BALB C; D009821:Oils; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects* / Q000276:immunology; D014867:Water
D016915:AIDS Vaccines; D000276:Adjuvants, Immunologic; D004655:Emulsions; D015488:HIV Antigens; D019302:HIV Envelope Protein gp160; D007074:Immunoglobulin G; D008081:Liposomes; D009821:Oils; D014867:Water