Fish Immunology (1+1)

16.2. Mode of action of b-1,3/1,6-glucans

Unit 16 - Immuno-stimulants

16.2. Mode of action of ß-1,3/1,6-glucans
ß-1,3/1,6-Glucans bind specifically to a “receptor molecule” on the surface of the immune cells that has been retained during evolution and is found in all animal groups from simple invertebrates to man. This is why ß-1,3/1,6-glucans have the same basic biological effect within the whole animal kingdom. When the immune cells are stimulated by ß-1,3/1,6-glucan, the cells become more active in engulfing, killing and digesting bacteria and at the same time they secrete signal molecules (cytokines) which stimulate the formation of new white blood cells. In vertebrates which have the specific immune system, the activated phagocytes produce cytokines which also activate antibody-producing lymphocytes. So ß-1,3/1,6-glucan if used as vaccine it enhances the efficacy. ß-1,3/1,6-glucans intern also contribute in growth, wound healing, repair of cells etc. Purified form of ß-1,3/1,6-glucan do not induce any antibody production which is an added advantage because the immune system will not be stimulated to waste antibody against immune-stimulant itself.
Immune-stimulants are being used in the aqua-culture sector and in traditional animal husbandry to reduce mortality due to infections and to improve general performance of animals.
Immune-stimulants when used may provide the benefits like:

• Reduce mortality due to opportunistic pathogens.
• Prevent virus disease
• Enhance disease resistance of farmed shrimp
• Reduce mortality of juvenile fish
• Enhance the efficacy of anti-microbial substances
• Enhance the resistance to parasites
• Enhance the efficacy of vaccines