Aluminium Salts: Perspectives in their use as Adjuvants

The adjuvant activity of aluminium salts was discovered more than 60 years ago (Glenny et al, 1926). Diphtheria toxoid was being purified by the addition of alum (KAISO4) followed by NaOH, which leads to the precipitation of a gel of Al (OH)3 according to the equation in Table 1. The toxoid adsorbs to the gel by ionic interaction, and Glenny found that the complex was more immunogenic than the free toxoid. Al (OH)3, and similar mineral gels (Table 1) are still the only adjuvants licensed for human use although, as other contributions to this volume should make plain, they are likely to be joined by others in the not too distant future. The wide application of aluminium salts in human vaccines has been reviewed elsewhere (Aprile and Wardlaw, 1966; Edelman, 1980).