Gut-associated lymphoid tissue in the large intestine of calves. II. Electron microscopy.
Scanning electron microscopy of lymphoid tissue in the large intestine of three germfree calves (age 3, 6, and 7 days) revealed two different units: propria nodules and lymphoglandular complexes (LGC). Propria nodules had lymphoid tissue predominantly in lamina propria and were covered by distinct follicle-associated epithelium which lacked goblet cells; nodules were surrounded by wide crypts, which were also lined by follicle-associated epithelium towards the luminal side. Lymphoglandular complexes had lymphoid follicles in the tunica submucosa; epithelial diverticulae extended through the muscularis mucosae branching into the lymphoid nodule. In centers of lymphoglandular complexes, protrusions of lymphoid tissue were covered with distinct follicle-associated epithelium. By transmission electron microscopy cells compatible with M cells in the small intestine of calves and cells with characteristics of both enteroabsorptive and M cells were found. Follicle-associated epithelium of propria nodules and lymphoglandular complexes differed only in the relative frequency of cell types.
Liebler
E M
EM
Institut f. Pathologie, Tierärztliche Hochschule Hannover, Federal Republic of Germany.
Pohlenz
J F
JF
Cheville
N F
NF
D000818:Animals; D002417:Cattle / Q000033:anatomy & histology*; D003106:Colon / Q000648:ultrastructure; D005856:Germ-Free Life; D007420:Intestine, Large / Q000648:ultrastructure*; D008221:Lymphoid Tissue / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning