scholarly journals The digestion and transmission of labelled immunoglobulin G by enterocytes of the proximal distal regions of the small intestine of young rats.

1977 ◽  
Vol 273 (2) ◽  
pp. 427-442 ◽  
Author(s):  
B Morris ◽  
R Morris
Keyword(s):  
Small Intestine ◽  
Immunoglobulin G ◽  
Young Rats

Nippostrongylus brasiliensis: the distribution of primary worm populations within the small intestine of neonatal rats

Parasitology ◽  
1974 ◽  
Vol 68 (3) ◽  
pp. 339-345 ◽  
Author(s):  
D. Conwil Jenkins
Keyword(s):  
Small Intestine ◽  
Primary Infection ◽  
Host Immunity ◽  
Nippostrongylus Brasiliensis ◽  
Neonatal Rats ◽  
Young Rats ◽  
Privileged Site ◽  
Day By Day

When neonatal rats were exposed to a small (200 larvae) primary infection of Nippostrongylus brasiliensis the worms that became established in the intestine were found in the mid-jejunum on both the seventh and the fourteenth day after infection. By day 21 most of the worms had migrated to the duodenum where they remained subsequently.When similar rats were exposed to a heavy primary infection (1500 larvae) the worms were found to be distributed along the length of the duodenum and jejunum by the seventh day. By day 28, however, a proportion of worms equal to that formerly located in the jejunum had been expelled, leaving a population of about 300 worms in the duodenum.It is suggested that the increased longevity of those worms that survive the effects of host immunity is dependent on their location at the duodenal site. The possibility is raised that the duodenum may be an immunologically privileged site for N. brasiliensis in young rats.

scholarly journals Distribution of immunoglobulin G receptors in the small intestine of the young rat.

1980 ◽  
Vol 85 (1) ◽  
pp. 18-32 ◽  
Author(s):  
R Rodewald
Keyword(s):  
Small Intestine ◽  
Immunoglobulin G ◽  
Specific Binding ◽  
Proximal Jejunum ◽  
Luminal Surface ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Absorptive Cells ◽  
Igg Receptors ◽  
Old Rats

Conjugates of horseradish peroxidase (HRP) and immunoglobulin G (IgG) were used to map the distribution of cell surface receptors that can bind IgG at 0 degrees C within the small intestine of 10-12-d-old rats. Luminal receptors are present only within the duodenum and proximal jejunum. In these locations, receptors are limited to absorptive cells that line the upper portion of individual villi. Near villus tips, receptors are relatively evenly distributed over the entire luminal plasmalemma. In the midregion of villi, receptors are unevenly distributed over the luminal surface. Receptors (a) specifically bind rat and rabbit IgG, (b) recognize the Fc portion of the immunoglobulins, and (c) bind at pH 6.0 but not pH 7.4. To determine whether IgG receptors are confined to the luminal portion of the plasmalemma, intact epithelial cells were isolated from the proximal intestine of 10-12-d-old rats and incubated with HRP conjugates at 0 degree C. The specific binding of rat IgG-HRP to cells at pH 6.0 indicates that IgG receptors, which are functionally similar to those found on the luminal surface, are also present over the entire abluminal surface of absorptive cells. These results are consistent with the transport of IgG to the abluminal plasma membrane in the form of IgG-receptor complexes on the surface of vesicles. Exposure of these complexes to the serosal plasma, which is presumably at pH 7.4, would cause release of IgG from the receptors. To assess possible inward movement of vesicles from the abluminal surface after discharge of IgG, intravenously injected HRP was used as a space-filling tracer in the serosal plasma. HRP could be visualized within the coated and tubular vesicles responsible for transport of IgG in the opposite direction. These vesicles may, therefore, provide a pathway whereby receptors shuttle between the luminal and abluminal surfaces of cells.

scholarly journals Localization of intestinal sucrase-isomaltase complex on the microvillous membrane by electron microscopy using nonlabeled antibodies

1978 ◽  
Vol 79 (2) ◽  
pp. 516-525 ◽  
Author(s):  
Y Nishi ◽  
Y Takesue
Keyword(s):  
Electron Microscopy ◽  
Small Intestine ◽  
Immunoglobulin G ◽  
Smooth Surface ◽  
External Surface ◽  
Membrane Surface ◽  
Fine Particulate ◽  
Rabbit Small Intestine ◽  
Intestinal Sucrase ◽  
Number Of Particles

Microvillous vesicles isolated from rabbit small intestine showed a trilaminar membrane with a rather smooth surface, which was apparently not affected by papain solubilizing sucrase-isomaltase complex or by trypsin unable to solubilize it. When microvilous vesicles or trysinized ones were incubated with immunoglobulin G against the sucrase-isomaltase complex or monovalent fragments therefrom, an apparently continuous electron-opaque layer approximately 180 A in width appeared around the external surface of vesicles. Such a layer was not formed on papainized vesicles. Microvillous vesicles and trypsinized ones negatively stained with phosphotungate showed a great number of particles protruding approximately 150 A from the membrane surface, but papainized vesicles did not. The particles existed close to one another and appeared to form a particulate layer 150 A in width on the surface. The antibodies, whether they were divalent or monovalent, increased the width of the layer to approximately 200 A and obscured the fine particulate structure of intact and trypsinized vesicles. Papainized vesicles retained their smooth surface upon interaction with antibodies. These results, together with those with the Triton-solubilized sucrase- isomaltase complex (Nishi and Takesue, 1978), J. Ultra-struct. Res., 62:1- 12), indicate not only that sucrase-isomaltase complexes are located close to one another on the membrane, but also that they or at least their protein portions protrude approximately 150 A from the surface of the trilaminar membrane.

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