Organization of the reticular network of rabbit Peyer's patches

Abstract

The organization of the network of collagen fibers of rabbit Peyer's patches was examined by scanning electron microscopy (SEM) in alkali-water macerated tissues. The relationship between this network and the reticular cells within it was further studied by SEM of ultrasonicated tissues. Collagen fibrils (about 60 nm in diameter) formed collagen fibers or sheets. There were sheets of collagen fibrils with numerous pores beneath the patch dome epithelium. Within the patches, collagen fibers repeatedly divided and fused, forming the reticular network. The reticular network within the follicle was looser than within the dome, the corona, or the interfollicular area. The latter three compartments showed similar structures and consisted of numerous intercommunicating small subcompartments. Reticular cells were in contact with groups of free cells lodged in these subcompartments within the reticular network. Reticular cell processes with numerous fenestrations embraced not only collage fibers forming the reticular network, but also sheaths of collagen fibers of blood and lymphatic vessels. Sheaths of collagen fibers of high endothelial venules and lymphatic vessels were also fenestrated, indicating the sites through which lymphocytes and other free cells migrate. These results indicate that the reticular network of Peyer's patches is organized so as to facilitate migration and lodging of free cells and thus facilitate antigen-to-cell and cell-to-cell interactions during an immune response. The naked areas on the collagen fibers seem to provide a scaffolding for free cells during their migration.

Ultrastructure of the reticular basement membrane in asthmatic adults, children and infants

“…Additionally, interstitial collagen contains fibrils that each have characteristic transverse bands termed D-periodicity with a repetitive band frequency of ,64-70 nm [15]. In contrast, reticulin is composed of fibrils that form a relatively tangled loosely packed network of fine fibrils with a diameter of ,20-40 nm and absent or at least much less obvious D-periodicity [16]. The term subepithelial fibrosis has been suggested and is variously applied by different investigators to describe the characteristic thickening of the RBM layer in asthma [8].…”

“…Ten children (age 10 (6-16) yrs) with difficult asthma were compared with nine nonasthmatic paediatric controls (age 11 (7)(8)(9)(10)(11)(12)(13)(14)(15)(16) yrs) undergoing bronchoscopy for other respiratory indications, as previously described [5]. Difficult asthma was defined as persistent symptoms requiring rescue bronchodilator therapy on .3 days?week -1 despite .1,600 mg?day…”

T Cell Migration in Three‐dimensional ExtracellularMatrix: Guidance by Polarity and Sensations

“…In the lymph node, fibers strands forming channels ("conduits") are oriented towards the follicular B cell zones (Gretz et al, 1997). In Peyer's patches, fiber strands converge towards the follicle domes, the area of antigen presentation (Ohtani et al, 1991;Ohtsuka et al, 1992). Hence, it was speculated that T cell trafficking pathways from the periphery to the locations of antigen-presentation is guided by the preformed reticular fiber network (Ohtsuka et al, 1992).…”

Spatial Organization of the Collagen and Elastin Fibers of the Lung in the Japanese Monkeys, <i>Macaca fuscata</i>

“…Under deep anesthesia, the thorax was opened, and a catheter was inserted into the aorta through which the (Ohtani, 1987(Ohtani, , 1989(Ohtani, , 1993aOhtani et al, 1988Ohtani et al, , 1991Ohtani et al, , 1993Kikuta et al, 1991 around the alveolar entrances showed a significant degree of zig-zag or spiral courses (Fig. 2).…”