Humoral Immune Response Against Orally Administered Human γ Globulin in the Carp

Abstract

Antibody production against orally administered human γ globulin (HGG) was examined in carp, to elucidate the immunological significance of the transport of proteins into blood circulation, observed in agastric fish species. Weekly administration of HGG via oral route into fish induced serum antibody against the protein, in a dose dependent manner. The antibody titer, however, decreased sharply from 4 weeks to 6 weeks after initial administration of the antigen, even with continued treatment. The antibody titer elevated again by intramuscular injection of the antigen, indicating the immune suppression is not owing to oral tolerance.