Evidence for a Primary Association between Immunoblasts and Small Gut

Selective induction of an immune response in human external secretions by ingestion of bacterial antigen.

“…An ingested antigeni could be absorbed from the gastrointestinal tract, enter the circulation, and after deposition in secretorx tissties, stimulate immunocompetent cells. This explanation is unlikely because circulatinig antigens should also induce a pronounced serum antibody response; this had not been observed in our experimenits or in investigations performed in other laboratories (6,17,19,29 (6,(17)(18)(19)(20)(29)(30)(31)(32) (32,(34)(35)(36)(37)(38)(39)(40). A conviiiciiig denionstration of the f'unctioin of Peyer's patclhes as sites for antigen stinmlilation of IgA prectirsor cells wvas provided FIGURE 1 Dynamics of the aggltitninii antib)ody respoinse to S. m71tutan.s ONIZ-176 in glaiidtilar seeretiolns aiter primairv (10) and secondary (20) Log2 agglutinin titer determined by microtitrations with 2 x 108 CFU/ml of formalin-killed S. mutatns a-e and g (20).…”

Late‐term fetal thymectomy does not prevent the development of gut‐homing T cells after birth

“…A role for antigen in the generation of gut-homing specificities is suggested, given the absence of antigen in the fetus and the massive antigen load in the gut after birth, which is associated with a major increase in cell traffic through the gut and gut-associated lymphoid tissues. In this context it should be noted that lymph-borne immunoblasts generated in the small intestine of adult animals home to the gut of neonatal rats 16 and to sterile, heterotopic transplants of syngeneic fetal gut, 17 indicating that fetal gut vascular endothelium is capable of selectivity transmitting gut blasts, thereby excluding a primary role for antigen in the mechanism of homing of these cells. Radiolabelled adult mouse spleen cells have also been shown to home to antigen-free grafts of fetal intestine.…”

The fate of activated T cells migrating through the body: rescue from apoptosis in the tissue of origin

“…Thus, when analyzing the migration of activated Tcells during the entry phase at the level of the HEV in vivo, the data do not support the view that activated lymphocytes selectively enter the tissue of origin [9,12,[32][33][34][35], although in v i m adhesion assays point in this direction [28, 361. [43]. Thus, the presentation of endogenous peptides in the context of tissue-specific restriction elements (MHC class I-B, summarized in [44]) might be involved in the induction of sitespecific proliferation [45].…”