Late-term fetal thymectomy does not prevent the development of gut-homing T cells after birth.
Tissue-specific circulation of T cells is a critical element in the integration of systemic immune responses. Current models of T-cell migration suggest that homing specificities of T cells for tissues such as gut and skin are generated outside the thymus as a result of activation of virgin T cells by antigen in lymph nodes. We have used the sheep fetus (which is immunologically virgin and contains no memory or effector T-cell subsets) to examine the migration of 51Cr-labelled T cells in vivo. We report that gut-homing T cells are not present in the fetus and that gut-homing T cells from postnatal lambs home normally to fetal gut. Fetal thymectomy performed immediately prior to birth failed to prevent the development of gut-homing T cells in postnatal life. Gut-homing specificities on T cells are thus acquired extrathymically.
Cahill
R N
RN
Laboratory for Foetal and Neonatal Immunology, University of Melbourne, Parkville, Victoria, Australia.
Kimpton
W G
WG
Washington
E A
EA
Dudler
L
L
Trnka
Z
Z
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D002465:Cell Movement / Q000502:physiology; D002860:Chromium Radioisotopes; D007422:Intestines / Q000276:immunology*; D012756:Sheep / Q000196:embryology / Q000276:immunology*; D013601:T-Lymphocytes / Q000502:physiology*; D013934:Thymectomy
D002860:Chromium Radioisotopes