title: Differential in situ expansion and gene expression of CD4+ and CD8+ tumor-infiltrating lymphocytes following adoptive immunotherapy in a murine tumor model system.
abstract: In previous reports, we demonstrated that adoptively transferred T cells homed to the tumor site (among other sites) and that amplification of immune responses occurred in situ leading to the generation of cytotoxic CD8+ tumor-infiltrating lymphocytes (TIL) and macrophages. The present report extends these findings and shows that following adoptive immunotherapy (AIT) of mice bearing the immunogenic transplanted methylcholanthrene-induced rhabdomyosarcoma (MCA/76-9) there was a differential expansion of CD4+ and CD8+ TIL, the numbers peaking on days 6 and 8, respectively. At this time, CD8+ TIL accounted for the majority of Thy-1+ cells. Northern analyses of RNA extracted from positively selected (by panning) Thy-1+, CD8+ and CD4+ TIL isolated 8 days after AIT indicated the following: in five separate experiments, CD4+ cells expressed three- to sixfold more interleukin (IL)2 mRNA and six- to eightfold more IL6 mRNA than CD8+ cells, while CD8+ TIL expressed three- to sixfold more IL2 receptor (IL2R) mRNA and four- to sixfold more interferon-gamma mRNA than CD4+ cells. TIL cultured in 10% fetal bovine serum failed to release IL2 over a 24-h period, whereas both IL6 and interferon-gamma activities were demonstrable. The level of IL2R mRNA expression was reflected by a vigorous proliferative response of CD8+ TIL to exogenous recombinant IL2 and only a low response by CD4+ cells suggesting that most of the CD4+ TIL were in the resting stage. This was confirmed when it was shown that the incubation of panned CD4+ TIL with IL2 supplemented with irradiated spleen cells and "spent" 76-9 tumor culture supernatant (as a source of antigen) induced expansion of TIL resulting in a population consisting of greater than 90% CD4+ TIL. The overall data suggest that the relatively deactivated state of the CD4+ TIL at this particular time reflects the status of the rejection process in terms of the absence or low concentration of stimulating tumor-associated antigen.
authors.affiliation: The Jackson Laboratory, Bar Harbor, ME 04609.
authors.forename: R
authors.initials: R
authors.lastname: Evans
authors.forename: T M
authors.initials: TM
authors.lastname: Duffy
authors.forename: S J
authors.initials: SJ
authors.lastname: Kamdar
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens; D015870:Gene Expression; D016219:Immunotherapy, Adoptive; D007371:Interferon-gamma / Q000235:genetics; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000628:therapy; D010641:Phenotype; D012333:RNA, Messenger / Q000032:analysis; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D007376:Interleukin-2; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D007371:Interferon-gamma