Testing time-, ignorance-, and danger-based models of tolerance.
In this study, we present data showing that tolerance to Ags in the periphery is not determined by the time at which the Ag appears, or by special properties of tissues in newborn mice or newly developing immune systems. We placed male grafts onto immunoincompetent female mice, allowed the grafts to heal for up to 5 mo, and then repopulated the recipients with fetal liver stem cells. We found that the newly arising T cells were neither tolerant nor ignorant of the grafts, but promptly rejected them, though they did not reject female grafts, nor show any signs of autoimmunity. We also found that the H-Y Ag was continuously cross-presented on host APCs, that this presentation was immunogenic, not tolerogenic, and that it depended on the continuous presence of the graft. In searching for the stimulus that might activate the host APCs, we analyzed mRNA expression with a highly sensitive real-time quantitative PCR assay. By using two different "housekeeping" molecules for comparison, we analyzed the message levels for several stress and/or inflammatory molecules in the healed grafts. We found that the long-healed grafts were not equivalent to "normal" skin because the healed grafts expressed lower levels of GAPDH. Altogether, these data suggest that acceptance vs rejection of peripheral tissues is not attributable to ignorance, timing-based tolerance, or special circulation properties of naive T cells in neonatal tissues. It is more likely attributable to an aspect of the context of Ag presentation that remains to be identified.
Ghost Lab, Section on T cell Tolerance and Memory, Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases/National Institutes of Health, Bethesda, MD 20892, USA. canderson@niaid.nih.gov
C C
CC
Anderson
J M
JM
Carroll
S
S
Gallucci
J P
JP
Ridge
A W
AW
Cheever
P
P
Matzinger
D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology / Q000473:pathology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D005260:Female; D006084:Graft Rejection / Q000235:genetics / Q000276:immunology / Q000473:pathology; D006182:H-Y Antigen / Q000276:immunology / Q000378:metabolism; D007108:Immune Tolerance / Q000235:genetics; D007249:Inflammation / Q000235:genetics / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D016513:Mice, SCID; D018448:Models, Immunological; D012737:Sex Factors; D016038:Skin Transplantation / Q000009:adverse effects / Q000276:immunology / Q000473:pathology; D013312:Stress, Physiological / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology; D013950:Thymus Gland / Q000637:transplantation; D013997:Time Factors; D014945:Wound Healing / Q000235:genetics / Q000276:immunology
D006182:H-Y Antigen