Antigen delivery to gut associated lymphoid tissue of rabbits

A rabbit model was developed so that antigens, microbes or potential mucosal vaccines could be delivered in multiple doses directly to the luminal surface of the gut associated lymphoid tissue (GALT) located in the cecal appendix. A polyethylene catheter was implanted surgically into the tip of the appendix. It exited the body wall and progressed subcutaneously around the thorax to the dorsocervical region where it was attached to a subcutaneous obturator. The catheters were flushed every day with sterile saline. To assess patency of the system, radiographic contrast media was injected and the animals were radiographed. Rabbits were necropsied at 10, 30 and 60 days and tissues evaluated by histological, immunohistochemical and electron microscopic means. The microbial flora was evaluated also. All tissues examined were free of significant abnormalities. The advantage of this delivery system is its ability to provide multiple doses of immunogenic agents directly to a physiologically normal appendix over an extended period.