The effect of adjuvants on active and passive immunity in pregnant deer and their offspring

Experiments were carried out to determine the effects of a range of adjuvants on immunoglobulin M (IgM) and immunoglobulin G (IgG) serum concentrations to a protein antigen administered subcutaneously to farmed female deer following mating. The antibody responses of animals immunised with keyhole limpet hemocyanin (KLH) in Freund's Incomplete Adjuvant (FIA), diethylaminoethyl dextran (DEAE-dextran) and aluminium hydroxide (alum) were compared with the response to antigen administered in the absence of adjuvants. Animals were subsequently challenged with a subcutaneous immunisation of the antigen in saline. Following parturition, the concentration of passively transferred antigen-specific antibody was measured in the serum of the offspring. The polyionic adjuvant, DEAE-dextran, produced the greatest enhancement of both primary and secondary IgG responses to KLH. Offspring suckling from mothers immunised with antigen in DEAE-dextran consequently had higher concentrations of specific antibodies in their serum than other fawns in the experiment. The adjuvants FIA and alum were approximately 20-fold less effective in enhancing antigen-specific IgG than DEAE-dextran but induced greater amounts of antigen-specific IgM. From the results presented in this paper, there is evidence that immunisation of deer during pregnancy may be an effective way of reducing morbidity in both mothers and offspring.