Effects of adjuvants on the immune response of pigs after intradermal administration of antigen.

The ability of different adjuvants to enhance immune responses to intradermal (ID) immunisation with a model antigen was studied in pigs. Immune responses were evaluated with respect to the intensity of systemic and mucosal antibody formation, their isotype characterisation and rate of cell-mediated immunity. These findings were compared with the intensity of adverse local reactions. Six groups of piglets were immunised with keyhole limpet haemocyanin (KLH) antigen alone or in combination with aluminium hydroxide or selected oil-based adjuvants (complete and incomplete Freund’s adjuvants, Montanide ISA 206 and Emulsigen). Systemic specific antibody responses were significantly increased following ID administration of antigen together with any of the adjuvants used. IgG antibody responses were most pronounced after the first administration of antigen, being stimulated with both Freund’s and Montanide ISA 206 adjuvants. The oil adjuvants also enhanced the cell-mediated immune responses and the levels of local IgA antibodies in the respiratory mucosa. On the other hand, they elicited more pronounced adverse local reactions.