Ovine cytokines and their role in the immune response.

Using a variety of expression systems the number of available recombinant ovine cytokines has increased steadily. This has led to the use of ovine cytokines as adjuvants to modulate the immune responses to vaccine antigens, both quantitatively and qualitatively. In addition DNA immunization, now common in mice, is being increasingly used in sheep. This may provide a unique avenue for the use of cytokines as immunomodulators, as it avoids preparing large quantities of biologically active recombinant protein and allows a slow, prolonged release of the cytokine at the same site as the antigen. As detection systems are developed their usefulness and shortcomings become apparent. The combination of cytokine detection, lymphatic cannulation and the in vivo neutralization of cytokines has allowed a greater understanding of the immune response during vaccination and of the interaction between pathogens and the immune system.