Enhanced Antigen-Specific Responses in Bovine Mammary Glands Following Administration of Interleukin-2

Abstract

This study examined the feasibility of using interleukin-2 as a vaccine adjuvant to enhance specific immunity in the bovine mammary gland. In trial 1, cows were immunized by intramammary infusion of keyhole limpet hemocyanin with either saline (n=3) or interleukin-2 (n=3) as adjuvants. In trial 2, cows were immunized by intramuscular injection near the supramammary lymph node with keyhole limpet hemocyanin in conjunction with saline (n=4). Freund's incomplete adjuvant (n=4). or interleukin-2 (n=4). Local immunization with interleukin-2 as an adjuvant significantly increased antibody titers in milk over preimmunization levels and levels in saline-treated cows. The use of Freund's incomplete adjuvant and interleukin-2 as adjuvants in cows that were immunized systemically enhanced both sera and lacteal antibodies to keyhole limpet hemocyanin. However, cows that were administered interleukin-2 responded more quickly than those given Freund's incomplete adjuvant. Only those cows that received interleukin-2 as an adjuvant demonstrated significant increases in blood lymphocyte proliferation to keyhole limpet hemocyanin, pokeweed mitogen, and interleukin-2. The results of these two trials suggest that immunization with interleukin-2 as an adjuvant may be more effective than Freund's incomplete adjuvant in enhancing specific immunity in the bovine mammary gland and may possibly be an effective adjuvant in mastitis immunization protocols.