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

¹ Department of Veterinary Science, Center for Mastitis Research, The Pennsylvania State University, University Park 16802

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.

Key Words: interleukin-2 • mastitis • vaccines • adjuvant

Submitted on July 20, 1994
Accepted on November 7, 1994