Immunologic adjuvant

From Wikipedia, the free encyclopedia

In immunology, an adjuvant is a component that potentiates the immune responses to an antigen and/or modulates it towards the desired immune responses.^[1] The word “adjuvant” comes from the Latin word adiuvare, meaning to help or aid.^[2] "An immunologic adjuvant is defined as any substance that acts to accelerate, prolong, or enhance antigen-specific immune responses when used in combination with specific vaccine antigens."^[3]
Adjuvants have been whimsically called the dirty little secret of vaccines^[4] in the scientific community. This dates from the early days of commercial vaccine manufacture, when significant variations in the effectiveness of different batches of the same vaccine were observed, correctly assumed to be due to contamination of the reaction vessels. However, it was soon found that more scrupulous attention to cleanliness actually seemed to reduce the effectiveness of the vaccines, and that the contaminants – "dirt" – actually enhanced the immune response. There are many known adjuvants in widespread use, including oils, aluminium salts, and virosomes.

Contents

• 1 Overview
  • 1.1 Inorganic adjuvants
    • 1.1.1 Aluminium salts
  • 1.2 Organic adjuvants
    • 1.2.1 Oil-based
  • 1.3 Virosomes
  • 1.4 Experimental adjuvants
• 2 Adjuvants and the adaptive immune response
• 3 Adjuvants and toll-like receptors
• 4 Medical complications
  • 4.1 Humans
  • 4.2 Animals
• 5 Controversy
• 6 Vaccine adjuvant database
• 7 See also
• 8 External links
• 9 References

Overview

Adjuvants in immunology are often used to modify or augment the effects of a vaccine by stimulating the immune system to respond to the vaccine more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionarily conserved molecules, so called PAMPs, which include liposomes, lipopolysaccharide (LPS), molecular cages for antigen, components of bacterial cell walls, and endocytosed nucleic acids such as double-stranded RNA (dsRNA), single-stranded DNA (ssDNA), and unmethylated CpG dinucleotide-containing DNA.^[5] Because immune systems have evolved to recognize these specific antigenic moieties, the presence of an adjuvant in conjunction with the vaccine can greatly increase the innate immune response to the antigen by augmenting the activities of dendritic cells (DCs), lymphocytes, and macrophages by mimicking a natural infection.^[6]