The effects of different adjuvants on intestinal antigen absorption and subsequent immune responses of the tilapian Oreochromis mossambicus

The effects of three potential adjuvants, cholera toxin β-subunit (CTB); aluminium hydroxide [Al(0H)3] and ammonium chloride (NH4Cl) on the absorption of human gamma globulin (HGG) from the gastrointestinal tract of the tilapian Oreochromis mossambicus, and subsequent antibody generation were investigated utilising specific ELISA assays. CTB increased the levels of HGG transcytosed into the plasma over levels observed after HGG delivery alone or delivery of HGG with either Al(OH)3 or NH4Cl. The enteric immunisation with HGG plus CTB or Al(OH)3 resulted in antibody titres that were raised above those observed after the enteric immunisation with the antigen on its own or with NH4Cl. Parenteral immunisation with each of the three adjuvants resulted in levels of specific antibodies similar to those achieved after immunisation with HGG alone.