Early Stages of Intestinal Absorption of Specific Antibodies in the Newborn

Abstract

In mammals, passive immunity is transferred from mother to offspring by transplacental passage or by intestinal absorption. The rabbit receives antibodies exclusively across the placenta, whereas intestinal absorption is the principal source of antibodies for the new-born pig. In the rat, passive immunity is transferred by both pathways. The role of the jejunal absorptive cells was investigated in these three species, by the use of specific immune globulins as tracers of protein absorption. Rabbit anti-peroxidase and anti-ferritin antibodies were injected into the jejunum of newborn pigs, rats, and rabbits, and absorption was studied over the first 2 hr. The specific antibodies were detected in glutaraldehyde-fixed tissues after in vitro treatment with the antigens, and in sera by immunological methods. Intact antibodies are transferred into the circulation of the pig and the rat, but not into that of the rabbit. In the three species, the jejunal absorptive cells take up antibodies by endocytosis. In the pig, the antibodies are transported across the epithelium in vacuoles. In the rabbit, the endocytosis of antibodies triggers a lysosomal response and all absorbed antibodies are trapped in lysosomes. In the rat, both situations are found; there is no evidence of transfer of antibody fragments into the circulation.

Protein Binding by Specific Receptors on Human Placenta, Murine Placenta, and Suckling Murine Intestine in Relation to Protein Transport across These Tissues

“…Yet, binding by the 60,000-g intestinal fraction from the 19-day-old or adult mouse is more than onethird of the binding observed with the intestinal fraction from young suckling animals. It is possible, that the decreased absorption of intact protein by the older animals may be due simply to increased intraluminal or intraepithelial protein digestion as has been suggested by others for the rabbit (32). Another possibility suggested by the data, however, is that an H-IgG transport system other than the cell receptor exists which is repressed or inhibited at 19-21 days of age.…”

Intestinal Transport of Antibodies in the Newborn Rat

“…VOLUME 58,1973 ruled out circumvential transport of tracer across regions of the intestine not under observation . Although certain studies have used the detection of specific antibodies in the lamina propria of the distal intestine to justify a transport role for distal cells (Clark, 1959 ;Kraehenbuhl and Campiche, 1969), it is significant that in these studies the distal intestine was not tied off from more proximal regions. In these experiments the proximal intestine, though not studied, was also exposed to the immunoglobulins and could have accounted for the observed transport .…”

“…However, because some authors (Kraehenbuhl and Campiche, 1969 ;Orlic and Lev, 1973) have not clearly distinguished between proximal and distal cells, the identifying characteristics of distal cells should be briefly noted .…”

“…Clark (1959) described a unique epithelial cell type in the lower jejunum and ileum of suckling rats which disappeared at an age when antibody transport ceased . Although a number of investigators (Clark, 1959 ;Kraehenbuhl et al ., 1967 ;Graney, 1965Graney, , 1968Kraehenbuhl and Campiche, 1969) have shown that these cells can concentrate a variety of tracers including antibodies, no clear evidence has been presented for selective binding or release of immunoglobulins from the cells . Nevertheless, it has been generally believed that these cells are responsible for transport of antibodies to the circulation (Clark, 1959 ;Anderson, 1963Anderson, , 1965Graney, 1965Graney, , 1968Bamford, 1966 ;Kraehenbuhl and Campiche, 1969) .…”

Localization of [alpha]-actinin and tropomyosin in muscle and nonmuscle systems

“…Fix atives contained 5 mM CaCl^, and their final osmolarity was adjusted with NaCl to 1050 mosmols/liter (Kraehenbuhl and Campiche, 1969). Samples remained in the fixative at 4°C for 2 hr and were then washed by flushing with 5 changes of cold 0.2 M Tris-HCl buffer, pH 7.4.…”