Fish Immunology (1+1)

Unit 15 - Adjuvants

15.2. Classification of adjuvants
Microbial/biological substances
These include Mycobacterium sp., M. tuberculosis incorporated in Freund's complete adjuvant (FCA), BCG, M. marinum, mixed bacterial toxins, cholera toxin beta unit, saponin including quil-A and immunostimulating complexes (ISCOMs), hemin and haemoglobin, crustaceans, insects and cell wall of certain fungi) etc .
Chemically defined yeast/bacterial/fungal products
Most important of these include lipopolysaccharides (LPS) such as β (1, 3)-D- glucan (laminaran), lentinan, muramyl dipeptide (MDP) and cord factor (trehalose dimycolate (TDM) of Mycobacteria, polar glycopeptidolipids (PGPL) of M. chelonae and peptidoglycan.
Biological products of immune system
They include lymphokines, cytokines, lactoferrin, growth hormones and prolactin.
Synthetic biological analogues
Double stranded complementary RNA homopolymers, synthetic MDP,synthetic TDM, lauroyl tetrapeptide, stearyl tyrosine hydrochloride, dimerized lysozyme, inosine pranobe, formyl peptide (FMLP), short chain peptide, and FK-565 (a peptide related to lactoyl tetrapeptide isolated from cultures of Streptomyces olivaceogriseus) are common adjuvants of synthetic biological analogues.
Chemical preparations
These include aluminium compounds like aluminium hydroxide, aluminium sulphate and aluminium phosphate, calcium phosphate, dextran sulphate, oil emulsions including mineral and vegetable oils in Freund's complete (FCA) and incomplete (FIA) adjuvants, wax D, levamisole, liposomes, polyacrylic adjuvants, serum albumen beads. CP-20, CP-960, synthetic polymers, squalene, rnicrosilica, quaternary ammonium compounds hydrocarbon adjuvants like aliphatic amines of chain length around C 16- like dimethyldioctade cyclamine and N,N-dioctadecyl-N-N-bis (2 hydroxyethyl) propanediamine.
The most commonly used adjuvant is Freund's complete adiuvant (FCA) because it serves as a storehouse for immunogen over a prolonged period thus helps in prolonged release of antigens. It is a combination of paraffin oil, lanonin-like substances and killed Mycobacterium sp. Its bacterial component stimulates T-cell response. Freund's incomplete adjuvant is used after FCA to enhance vaccine effect, this adjuvant doesn't contain bacterial component as in FCA. Other commonly used adjuvants are light oils and lipopolysaccharides.