Histomorphological Studies on the Gut-associated Lymphatic Tissues (GALT ) in Rabbit

Abstract

The aim of this study was to reveal histomorphological characteristics of gut-associated lymphoid tissue (GALT) in rabbit that included ileal peyer’s patch, sacculus rotundus (SR) and vermiform appendix (VA); the later two structures being specific to rabbits only. The first appearance of the lymphocytic aggregation marked the jejuno-ileal junction that were more organized at the terminal part of the ileum in the form of nodules (peyer’s patch). The GALT were formed of lymph nodules covered by low columnar epithelium containing intraepithelial lymphocytes. The nodules were completely filled with medium to large sized lymphocytes and few plasma cells. The lymph nodules in the peyer’s patch was in direct contact with the lumen, while those of the SR and VA were covered by the mushroom and umbrella shaped mucosal folds respectively. In the peyer’s patch, GALT was composed of dome region and germinal center and were separated by narrow inter-follicular areas, whereas, that of the sacculus rotundus and the appendix were composed dome region, germinal center and coronal area but inter-follicular space was absent. The huge lymphocytic aggregation in the form of nodules in the VA and SR implied the role of local immune response specifically in case of the rabbit that might play a major role as primary lymphoid organ.