Evidence has been reported that the proximal small intestine of the neonatal rat selectively transports antibodies into the circulation. This study describes the morphology of the absorptive epithelial cells in this region of the intestine and their transport of several immunoglobulin tracers: ferritin-conjugated immunoglobulins (IgG-Ft) and antiperoxidase antibodies. Cells exposed to rat IgG-Ft bound the tracer on the membrane of tubular invaginations of the apical cell surface. Tubular and coated vesicles within the cell also contained the tracer, as did the intercellular spaces. Uptake of tracer was highly selective and occurred only with rat or cow IgG-Ft; when cells were exposed to chicken IgG-Ft, ferritin-conjugated bovine serum albumin, or free ferritin, tracer did not enter the cell or appear in the intercellular spaces. Experiments with rat and chicken antiperoxidase showed a similar selective uptake and transport of only the homologous antibody. When cells from the distal small intestine were exposed to the tracers, all tracers were absorbed nonselectively but none were released from the cells. Cells from the proximal small intestine of the 22-day-old rat failed to absorb even rat IgG-Ft. A model is presented for selective antibody transport in proximal cells of the neonatal rat in which antibodies are selectively absorbed at the apical cell surface by pinocytosis within tubular vesicles. The antibodies are then transferred to the intercellular space within coated vesicles. Distal cells function only to digest proteins nonselectively.
Article| July 01 1973
INTESTINAL TRANSPORT OF ANTIBODIES IN THE NEWBORN RAT
From the Department of Biochemistry, School of Medicine, University of Pennylvania, Philadelphia, Pennsylvania 19104.
Dr. Rodewald's present address is the Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115.
Received: December 12 1972
Revision Received: February 16 1973
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1973 by The Rockefeller University Press
Richard Rodewald; INTESTINAL TRANSPORT OF ANTIBODIES IN THE NEWBORN RAT . J Cell Biol 1 July 1973; 58 (1): 189–211. doi: https://doi.org/10.1083/jcb.58.1.189
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