title: Radiosensitive barrier to T-cell-mediated adoptive immunotherapy of established tumors.
abstract: This study shows that it is not possible to cause regression of the immunogenic SA-1 sarcoma by adoptive immunotherapy with tumor-sensitized T-cells, unless the tumor-bearing recipient is exposed to a sublethal dose of gamma-irradiation to remove a barrier that prevents adoptive immunity from being expressed. This barrier to adoptive immunotherapy was found to be regenerated between 2 and 4 weeks following irradiation, and its regeneration was associated with general repopulation of host T-cells. However, it was not regenerated in the absence of the thymus, thus showing that it is T-cell dependent. Evidence that it is caused by the presence of CD4+ suppressor T-cells was shown by the finding that it can be removed by depleting mice of CD4+ T-cells with anti-L3T4 monoclonal antibodies, but not by depleting them of CD8+ T-cells with anti-Lyt-2 monoclonal antibodies. Again, the barrier could be restored to irradiated recipients by infusing them with CD4+ T-cells, but not with CD8+ T-cells, from tumor-bearing donors. The barrier to adoptive immunotherapy was found to be tumor induced and to be paradoxically generated in concert with host concomitant immunity.
authors.affiliation: Trudeau Institute, Saranac Lake, New York 12983.
authors.forename: M
authors.initials: M
authors.lastname: Awwad
authors.forename: R J
authors.initials: RJ
authors.lastname: North
mesh_terms: D000818:Animals; D005720:Gamma Rays; D007116:Immunization, Passive; D051379:Mice; D008815:Mice, Inbred Strains; D012513:Sarcoma, Experimental / Q000276:immunology / Q000628:therapy*; D013154:Spleen / Q000276:immunology / Q000528:radiation effects; D013601:T-Lymphocytes / Q000276:immunology* / Q000528:radiation effects / Q000637:transplantation