The advances

in vaccine technology have initiated a future of novel and innovative vaccine designs based on new knowledge of the antigenic properties of pathogens and the ways in which a protective immune response might be induced. “
“Key concepts ■ Adjuvantation of vaccines is a well-established concept and practice The adjuvant concept is more than 80 years old with the first adjuvant present in human vaccines, an aluminium salt (aluminium potassium sulphate, also known as alum), appearing in the 1920s. About 70 years later a licensed vaccine with an alternative adjuvant to aluminium salt was developed ( Figure 4.1). The addition of components other than the pathogen or antigen to vaccine PS341 preparations represents one of the original attempts to improve vaccine efficacy. Adjuvants are substances that can enhance and modulate the immunogenicity of the vaccine antigen. In a vaccine, the specificity of the immune response is provided by the antigen and the role of the adjuvant is to TSA HDAC mouse amplify this immune response. Live vaccines

usually do not require adjuvants as they mimic natural infection and are therefore ‘naturally adjuvanted’. Most inactivated (whole or subunit) vaccines do require adjuvants since the inactivation processes remove, in part or totally, the pathogenic features of the microorganisms that are responsible for triggering the immune response. Inactivated vaccines may retain some of the characteristics that stimulate the innate

immune system (ie pathogen-associated molecular patterns [PAMPs], see Chapter 2 – Vaccine immunology), but the amount and context of these PAMPs may be insufficient to provoke long-lasting immunity. Aluminium salts have been sufficient to induce an adequate immune response for most of the licensed inactivated and subunit vaccines. However, many of the modern vaccines consist of highly purified antigens for which the natural innate immune triggers are not present. These refined formulations often show reduced immunogenicity and therefore require adjuvantation. Classic aluminium salts are not always capable of eliciting Thiamet G the desired immune response and more complex adjuvantation may be required. One of the promising approaches to improve efficacy of newly developed prophylactic and therapeutic vaccines is the use of innovative adjuvants including the technique of combining different types of adjuvants into single formulations. Adjuvant selection There is no universal adjuvant to cover all vaccine needs. The appropriate selection of adjuvants to match the antigens is key to the formulation of novel and efficacious vaccines. For example, different aluminium salts (phosphate or hydroxide) are used depending on the ion charge required for binding to the antigen.