Modifications of the follicle-associated epithelium by short-term exposure to a non-intestinal bacterium.
This study was undertaken in order to study the effects of short-term exposure of the follicle-associated epithelium (FAE) of rabbit Peyer's patches to a non-intestinal, Gram-positive bacterium. Isolated ileal loops, each containing one Peyer's patch (PP), were stimulated for short periods of time (30 and 60 min) with Streptococcus pneumoniae R36a, a micro-organism normally not present in the intestinal area. Samples from antigen-stimulated and control Peyer's patches were analysed by light (LM), transmission electron (TEM), and scanning electron microscopy (SEM). Stimulation with living pneumococci induced dramatic changes in FAE architecture and morphology. A massive passage of cells from lymphoid tissue to the FAE was rapidly detectable, accompanied by alterations of the FAE surface, with a marked increase of M-cell area. Furthermore, TEM analysis revealed that M cells were able to internalize living pneumococci. S. pneumoniae R36a is a valid experimental model for the further study of the unique antigen sampling function which characterizes the highly specialized FAE in Peyer's patches.
Borghesi
C
C
Institute of Human Anatomy, University of Siena, Italy.
Regoli
M
M
Bertelli
E
E
Nicoletti
C
C
D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000276:immunology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D018448:Models, Immunological; D010581:Peyer's Patches / Q000276:immunology* / Q000648:ultrastructure; D011817:Rabbits; D013296:Streptococcus pneumoniae / Q000276:immunology*
D000942:Antigens, Bacterial