Comparison of 24 different adjuvants for inactivated HIV-2 split whole virus as antigen in mice. Induction of titres of binding antibodies and toxicity of the formulations

Abstract

The objective of this study was the comparison of the quantity and quality of the humoral immune response against inactivated whole human immunodeficiency virus type 2. Twenty-four different adjuvants were tested. The toxicity of these preparations was determined. Due to the large number of experiments, the animal model used was the NMRI mouse. Sera were assayed for the presence of antibodies by ELISA and Western blot. The toxicity of the adjuvants was determined by observing lethal side-effects occurring within two days after injection of the immunogenic preparations. The results show that polymethylmethacrylate nanoparticles were the best overall adjuvant, inducing the highest titres of antibodies compared with other adjuvants as well as producing a significantly better immune response against a number of individual HIV-2 antigens without any observable toxic side-effects. However, this adjuvant did not induce antibodies against the outer envelope protein gp120, whereas such antibodies were induced by aluminium compounds, Freund's complete and incomplete adjuvants, and fumed silica (Aerosil). This result suggests the necessity of using vaccines with two or more different adjuvants in order to induce the required immune response against physically different antigens.